Toward quantifying disability in spontaneous intracranial hypotension: A patient-derived disability weight

Abstract

Introduction

Spontaneous intracranial hypotension (SIH) due to a spinal CSF leak is associated with substantial health loss. However, SIH is not represented as a distinct condition in the Global Burden of Disease framework, and no disease specific disability weight has been reported. A disability weight is the fundamental basis for comparative analyses of disease burden. The objective of this study was to estimate a patient-derived disability weight for SIH based on pre-treatment health-related quality of life data and to contextualize this estimate relative to published values for other conditions.

Methods

We conducted a retrospective observational study of consecutive patients with confirmed spinal CSF leaks treated at a tertiary referral center between October 2020 and October 2025. Pre-treatment quality of life and headache burden were assessed using the EQ-5D-5L and HIT-6 questionnaires. After calculating the EQ-Index using the German value set, the mean disability weight and its 95% confidence interval were derived using a linear transformation. For contextual interpretation, the newly estimated disability weight was compared descriptively with published values for deliberately selected neurological, headache- or pain-related, and chronic conditions.

Results

A total of 321 patients with confirmed spinal CSF leaks before targeted treatment were included (60.4% female; median age 47 years [IQR 37–56.). Most patients had a ventral leak (192/321, 60%), followed by CSF–venous fistulas (67/321, 21%) and lateral leaks (62/321, 19%). The mean EQ-Index was 0.568 (95% CI 0.533–0.603), the median EQ-VAS was 45.5 (IQR 30–65). The median HIT-6 score was 65 (IQR 59–68). All scores showed no significant differences between the three leak types. Based on EQ-5D-5L data, the resulting mean disability weight for SIH was 0.432 (95% CI 0.40–0.47).

Conclusion

This study provides a first patient-derived disability weight estimate of 0.432 for ongoing SIH. This indicates a substantial non-fatal health loss that is comparable to or exceeding that of other chronic conditions. This estimate enables contextual comparison with other conditions and provides a foundation for future burden-of-disease assessments of this curable condition.

Graphical abstract

This is a visual representation of the abstract.

Keywords

spontaneous intracranial hypotension disability weight health-related quality of life global burden of disease

Introduction

Spontaneous intracranial hypotension (SIH) is a debilitating disorder that typically affects otherwise healthy adults between 20 and 60 years of age, frequently during their most productive years of life.^1–3 In contrast to primary headache disorders such as migraine, cluster headache, or new daily persistent headache, SIH represents a secondary and often chronic head and neck pain syndrome with a clearly identifiable and directly treatable cause–a spontaneous spinal cerebrospinal fluid (CSF) leak. Previously regarded as an ultra-rare and largely benign disease, current estimates suggest an annual incidence rate of approximately 4/100,000^1,4 corresponding to roughly 300.000 new cases worldwide per year.⁵ Although the rate of spontaneous resolution remains uncertain, it is well established that persistent SIH is associated with a substantial reduction in health-related quality of life^6,7 significant headache related disability,^2,8,9 and a broad spectrum of comorbid symptoms including vestibulocochlear disturbances, cognitive impairment, and depressive symptoms.^2,10,11 Moreover, SIH may lead to severe and potentially irreversible complications such as sinus venous thrombosis, chronic subdural hematomas, and superficial siderosis.^3,12,13 Taken together, ongoing SIH is by no means “benign” and associated with considerable direct and indirect costs, resulting in a high individual and socioeconomic burden if left untreated.¹⁴ Owing to recent advances, including the identification of novel entities such as CSF-venous and CSF-lymphatic fistulas,^15,16 there has been rapid improvement in diagnostic knowledge, technical expertise, and awareness of SIH. Nevertheless, SIH care is demanding in regards of interdisciplinary resources and expertise and might therefore be systematically underestimated and inadequately compensated. There is an increasing need to position SIH alongside other comparable diseases as a measurable and recognizable health burden in order to establish a foundation for policy changes that reflect the burden of the disease on the patient and society.

To quantify and compare disease burden across conditions at the individual level, the Global Burden of Disease (GBD) studies, coordinated by the World Health Organization and the Institute for Health Metrics and Evaluation have introduced standardized metrics that allow direct comparisons across countries and over time.^17–19 Central to this framework is the disability weight (DW), which represents the severity of health loss associated with a specific condition on a scale from 0 (full health) to 1 (equivalent to death).²⁰ It reflects the degree to which a disease reduces overall health and functioning, and serves as a foundational element for comparative burden estimates. Originally, these disability weights have been derived by paired comparisons by the GBD studies that did not include SIH at the time.

Despite its clear clinical impact and growing recognition over the past decade, SIH remains absent as a distinct entity within Global Burden of Disease classifications, and no disease-specific DW has been reported.^17–20 The primary objective of this study was therefore to derive a patient-based DW for SIH using validated health-related quality of life measures. We hypothesized that ongoing SIH is associated with substantial non-fatal health loss comparable to other conditions.

Methods

We conducted a retrospective, monocentric observational study of consecutive patients with SIH diagnosed and treated at a tertiary referral center. Definitive SIH was defined as patients with spontaneous spinal CSF leaks depicted and classified by dynamic (digital subtraction) myelography and/or dynamic CT myelography regardless of individual symptoms which are commonly known to be multifaceted.^2,9–11^,21 The study was approved by the local Ethics Committee (24-1296-S1-retro, 24-1357-S1) and followed the guidelines of the STROBE statement.²² All patients admitted between October 2020 and October 2025 with confirmation of a spinal CSF with dynamic digital subtraction myelography and/or dynamic CT myelography, and with available patient-reported outcome data before targeted treatment were included. All patients agreed to the anonymized evaluation of their demographic and quality of life data, individual written informed consent was waived due to the strictly retrospective design in accordance with institutional guidelines

Demographic and clinical data: Age in years, country of origin, Sex as given at birth, prior treatment (conservative treatment, epidural blood patches, targeted treatments), symptom duration and spinal CSF leak type according to Schievink et al.²³ were retrieved from the systematically managed internal database.

Patient reported outcome measures (PROMs): PROMs were collected prior to definitive closure of the spinal CSF leak, reflecting the patients’ health status during the persisting disease phase. The health-related quality of life impairment was assessed using the EuroQol questionnaire (EQ-5D-5L), and headache burden by the 6-item Headache Impact Test (HIT-6). The EQ-5D-5L assesses quality of life regardless of an underlying disease by covering the impairment in five relevant dimensions of daily life (mobility; self-care; daily activities; pain/discomfort; anxiety/depression) on a five-point scale.²⁴ The level of impairment in all functional dimensions regardless of its cause is converted into a score (EQ-Index) between 1.000 and <0 by using a country-specific scoring algorithm.^24,25 EQ-Index values were calculated using the German value set.²⁵ An EQ-Index value of 1 represents full and unimpaired health, a score of 0 represents “dead”, negative values (<0) are also possible, representing states of “worse than dead”. Included in the EQ-5D-5L is a visual analogue scale (EQ-VAS), that rates the current quality of life on a scale from 0 (worst imaginable health) to 100 (best imaginable health). Its widespread and interdisciplinary use across a variety of diseases, including SIH, makes the EQ-5D-5L suitable as a global comparator facilitating comparability of quality of life between different conditions. The HIT-6 assesses the impact of headaches on daily life over the past four weeks.²⁶ Possible scores range from 36 to 78 points, with higher scores indicating a more significant impact and scores below 50 points indicating no or little impact. The HIT-6 has been extensively utilized in several headache disorders (including migraine, cluster headache, trigeminal neuralgia), as well as in SIH.²⁷ HIT-6 values do not directly correspond to designated quality of life instruments such as the EQ-5D-5L, however, they do facilitate the comparison of headache impact across different headache disorders.

Statistical analysis and estimation of the disability weight

Analyses were conducted using R (version 4.3.2). The presence of a normal distribution was assessed using the Shapiro-Wilks test. In the case of nonnormally distributed data, the median with the interquartile range (IQR), in the case of normal distribution, the mean with standard deviation (SD) and their respective 95% confidence interval was reported. To determine whether age, duration of the leak, and PROM scores differed between the three leak types, a Kruskal–Wallis test with post-hoc Bonferroni corrections was conducted. An alpha-level of p<0.05 was considered significant. DW were derived using the EQ-Index using the linear transformation DW = 1–EQ-Index.^28–31 This approach reflects the proportion of health loss experienced by the patient and has been widely applied in previous burden-of-disease and health-economic research^{18,19,28–31} when condition-specific DWs are not available. The mean DW for SIH cohort was calculated from the cohort mean EQ-Index value, and a corresponding 95% confidence interval was derived using standard error–based confidence limits (SE = SD/ √n) from the distribution of EQ-Index values, relying on the asymptotic normality of the sample mean.^32,33 This patient-derived DW estimate reflects proportional health loss based on EQ-Index utilities and does not replicate the population-based health-state valuation procedures used in the Global Burden of Disease framework. Consequently, the derived value represents a utility-based estimate of health loss rather than an official GBD disability weight.

Comparative interpretation of the new estimated SIH disability weight with available values

To contextualize the newly mathematically derived DW for SIH, we performed a comparative interpretation using published disability weights and quality of life data for other conditions. Comparator conditions were deliberately selected to represent a broad spectrum of primary headaches, neurological and psychiatric disorders, as well as oncologic and chronic diseases, commonly associated with relevant functional impairment. The selection included chronic and episodic migraine, cluster headache, trigeminal neuralgia, multiple sclerosis, depression, breast and lung cancer, and rheumatoid arthritis in different stages, and chronic renal failure. For each comparator condition, published DWs were extracted from the Global Burden of Disease studies, and were reported on the original GBD scale, where 0 represents full health and 1 represents death.^17–20 Corresponding PROMs (EQ-Index, EQ-VAS, HIT-6) for comparator conditions were identified through a targeted literature search in PubMed using Medical Subject Headings (MeSH) for the respective diseases (e.g., “migraine”, “cluster headache”, “multiple sclerosis”) combined with terms related to health-related quality of life (e.g., “EQ-5D-5L”, “HIT-6”). Searches covered studies published up to 2025 and were limited to English-language articles in adult populations. The literature search was not intended as a systematic review but to provide contextual reference values for comparative interpretation.

Results

Study cohort

Between October 2020 and October 2025, 389 patients had the confirmed diagnosis of a spontaneous spinal CSF leak. For 68 patients, no PROM data was available, which lead to their exclusion of the study (Figure 1). There were no significant differences between included and excluded patients concerning sex, leak type, and symptom duration. However, excluded patients were significantly older, mainly due to the fact that they refused or had technical difficulties to complete the questionnaires. Finally, a total of 321 cases with a confirmed spinal CSF leak were included (Table 1). Of these, 194 (60.4%) were female. The median age was 47 years (IQR 37–56) ranging from 10 to 78 years. The predominant part of patients (271/321, 84%) lived in Germany, 49/321 (15%) lived in different, mainly western European countries, one patient lived in South Africa. The majority of patients (192/321, 60%) had a ventral leak (Type 1) and 62/321 (19%) had a lateral leak (Type 2), which were confirmed in dynamic (digital subtraction) myelography in prone or lateral decubitus position followed by occasionally followed by dynamic CT myelography when appropriate.^34,35 Among the patients with dural tears (Type 1 or Type 2 leaks), only one patient (female, 53 years of age) had two concurrent lateral leaks which were simultaneously closed in one surgery. The remaining rest had one single responsible dural tear. Finally, 67/321 (21%) had a CSF-venous fistula (Type 3), all of which were confirmed via CT-myelography in lateral decubitus position. Among the CSF-venous fistula cases, 9/67 patients (13%) had two fistulas, both of which were addressed in subsequent treatment. There was a significant age difference between the three leak types: Patients with lateral leaks (median 38 years ([IQR 30–47]) were significantly younger than patients with ventral leaks (median 46 years ([IQR 38–53]), and patients with CSF-venous fistulas (median 59 years ([IQR 53–65]) (p<0.001, respectively). Lateral leaks (79% vs 31%) and ventral leaks (58% vs 42%) showed a predominance for female sex whereas CSF-venous fistulas were equally distributed (49% vs 51%). The median symptom duration before diagnosis of the CSF leak was 7 months (IQR 3–19.8) with a range from 9 days to 42 years. Before the index treatment for definite closure of the leak in our institution, 176 patients received one or several epidural blood patches, 15 had one or more surgical interventions at an external institution without successful closure of the leak, and 130 patients had received only conservative treatment.

Figure 1.

Flowchart displaying the patient selection.

Table 1.

Results.

			All patients (all leak types combined)		Ventral leaks (Type 1)		Lateral leaks (Type 2)		CSF-venous fistulas (Type 3)
Patient characteristics			n = 321		n = 192		n = 62		n = 67
Sex	male / female		127 / 194		80 / 112		13 / 49		34 / 33
Sex	male / female		39.6% / 60.4%		41.7% / 58.3%		21.0% / 79.0%		50.7% / 49.3%
				Range		Range		Range		Range
Age	years	Median (IQR)	47 (IQR 37–56)	10–78	46 (IQR 38–53)	26–77	38 (IQR 30–47)	10–78	59 (IQR 53–65)	26–78
(skewed distribution)
Body Mass Index (BMI)	kg/m²	Median (IQR)	23.9 (21.7–27.4)	13.8–41.5	24.1 (22.0–27.7)	16.9–38.5	22.4 (20.4–25.0)	13.8–41.5	24.8 (22.6–28.5)	18.4–38.5
(skewed distribution)
Duration of symptoms	days	Median (IQR)	217 (IQR 97–609)	9–15425	184 (IQR 84–592)	9–8913	219 (IQR 115–474)	31–4031	334 (IQR 152–734)	20–15425
Duration of symptoms	months	Median (IQR)	7 (IQR 3–19.8)	0–506	6 (IQR 2–19)	0–292	7 (IQR 3–15)	1–132	11 (IQR 4.5–23.5)	0–506
(skewed distribution)
Scores
EQ Index		Mean (95% CI)	0.568 (0.533, 0.603)	−0.570–1.000	0.580 (0.535, 0.625)	−0.570–1.000	0.494 (0.403, 0.585)	−0.485–1.000	0.603 (0.535, 0.670)	−0.098–0.970
(skewed distribution)		Median (IQR)	0.655 (IQR 0.343–0.813)		0.690 (IQR 0.385–0.816)		0.498 (IQR 0.223–0.809)		0.690 (IQR 0.353–0.806)
EQ VAS		Mean (95% CI)	47.5 (45.1, 49.8)	0–100	48.5 (45.3, 51.6)	5–100	46.3 (41.0, 51.7)	0–90	45.7 (40.6, 50.8)	0–90
(skewed distribution)		Median (IQR)	45.5 (IQR 30–65)		50 (IQR 30–65)		43 (IQR 30–62.5)		40 (IQR 30–60.5)
HIT-6		Mean (95% CI)	62.5 (61.4, 63.5)	36–78	63.2 (61.9, 64.4)	36–78	62.7 (60.4, 65)	36–78	60.3 (57.3, 63.2)	36–78
(skewed distribution)		Median (IQR)	65 (IQR 59–68)		65 (IQR 59.5–70)		65 (IQR 59–68)		64.5 (IQR 57–68)

Patient-reported outcome measures

The median EQ-Index was 0.655 (IQR 0.343–0.813; 95% bootstrap CI 0.603–0.712), and the mean EQ-Index was 0.568 (SD ±0.32; 95% CI 0.53–0.60). The median EQ-VAS was 45.5 (IQR 30–65), and the median HIT-6 score was 65 (IQR 59–68). The majority of patients reported a significant impact of headaches on their daily lives as particularly burdening symptom: 261/321 patients (81%) experienced a substantial or severe impact of headaches (represented by HIT-6 scores ≥56) and only 39/321 patients (12%) had no or little impact of headaches (represented by HIT-6 scores ≤49). There were only marginal variations in all patient-reported outcomes without statistically significant differences between the three leak types, respectively (Table 1).

Estimation of the disability weight

Applying the equation DW = 1− EQ-Index to the cohort mean EQ-Index value of 0.568 resulted in a mean disability weight of:

\begin{aligned} DW = 1 - 0.568 = 0.432 \\ DW = 0.432 \end{aligned}

The corresponding 95% confidence interval for the mean disability weight was 0.40–0.47.

Comparative interpretation of the estimated SIH disability weight with other conditions

The targeted literature search identified 37 studies of the deliberately selected conditions that reported one or more of the PROMs (Table 2, Figure 2). The complete reference list of the retrieved 37 studies can be found in the supplementary material. Oncological conditions showed stage-dependent DWs, ranging from 0.288 in primary breast and lung cancer to 0.540 in terminal disease states.¹⁸ Among headache-related disorders, available DWs are 0.441 for the ictal state of migraine and 0.434 for cluster headache episodes. For chronic pain and inflammatory conditions, available DWs for rheumatoid arthritis are 0.317 in moderate disease and 0.581 in severe disease. For affective disorders, available DWs for major depressive disorder are 0.389 for moderate depression and 0.658 for severe depression. DWs for neurological disorders such as multiple sclerosis varied by disease severity, ranging from 0.183 in mild disease to 0.719 in severe disease. Figure 2 presents the disability weight estimated for SIH alongside published disability weights and corresponding patient-reported outcome measures for the selected comparator conditions, as summarized in Table 2.

Figure 2.

Graphical illustration of already available Disability Weights (DW, straight bar with the numerical value, respectively) together with patient-reported measures for quality of life via EQ-Index (represented by a dot) and EQ-VAS (represented by a square) as well as headache burden via HIT-6 score (represented by a triangle) for the deliberately selected neurological, headache- or pain-related, and chronic conditions. A higher position on the y-axis represents a more unfavorable health status, a more severe disability resulting in a higher DW. Each symbol represents a result (mean or median as reported, respectively) from one of the 37 studies (also presented in Table 2, complete reference list in the Supplements) retrieved in a selective literature review. On the far-right side, the results of the current study (mean values) as well the newly derived DW of 0.432 for spontaneous intracranial hypotension (SIH) are illustrated. Notably, as this DW was estimated via a pragmatic utility-derived approach, comparisons with official Global Burden of Disease DW must be interpreted as contextual rather than methodologically equivalent.

Table 2.

Previously published disability weights (DW) and patient-reported measures for quality of life (via EQ-Index and EQ-VAS) as well as headache burden (via HIT-6 score) for deliberately selected neurological, headache- or pain-related, and chronic conditions. The estimated DW for SIH in the present cohort was 0.432 and is presented alongside these reference conditions on the same GBD disability-weight scale. The complete reference list of the studies is found in the Supplements.

	Disability weight according to institute for health metrics and evaluation, 2024	Chronic (C) vs episodic (E)	Reference (see the list of these references in the supplementary material)	EQ-Index	EQ-VAS	HIT-6
				&=Mean	&=Mean	&=Mean
				$=Median	$=Median	$=Median
Migraine	0.441	C	Takizawa et al., 2025¹			59.7 (&)
		E	Yang et al., 2011²			60.2 (&)
		C	Yang et al., 2011²			62.5 (&)
		E	Oliveira Gonçalves et al., 2022³	0.842 (&)	70.7 (&)	64.4 (&)
		C	Oliveira Gonçalves et al., 2022³	0.689 (&)	58.0 (&)	65.2 (&)
		E	Domitrz and Golicki, 2022⁴	0.922 (&)	74.5 (&)
		C	Domitrz and Golicki, 2022⁴	0.822 (&)	63.4 (&)
		E	Díaz-Insa et al., 2024⁵	0.52 ($)	60 ($)
		C	Díaz-Insa et al., 2024⁵	0.35 ($)	40 ($)
		C	Lipton et al., 2025⁶	0.76–0.77 (&)	64.4–65 (&)
		E	Lipton et al., 2025⁶	0.85–0.87 (&)	76.2–76.6 (&)
		C E	Stafford et al., 2012⁷	-0.20–0.66 (&)
Cluster Headache	0.434	C	Mwamburi et al., 2020⁸	0,83 (&)
		C	Fontaine et al., 2017⁹	0.34–0.41 (&)	28–36 (&)	67–71 (&)
		C	Leplus et al., 2021¹⁰	0.40 (&)	36 (&)	68 (&)
		C	Leplus et al., 2021¹⁰	0.38 ($)	31 ($)	68 ($)
		C E	Kim et al.,2022¹¹			67.4–69.8 (&)
Trigeminal Neuralgia	0.291	E	Kotecha et al., 2017¹²	0.525 (&)	57 (&)
		E	Wang et al., 2025¹³
		E	O’Callaghan et al.,2020¹⁴	0.864 (&)	72.6 (&)
		E	O’Callaghan et al.,2020¹⁴	0.939 ($)	81 ($)
Mild multiple Sclerosis	0.183	C	Young et al., 2025¹⁵	0.797(&)
		C	Claflin et al., 2023¹⁶	0.80 (&)
		C	Campbell et al.,2023¹⁷	0.71 (&)
Moderate multiple Sclerosis	0.463	C	Young et al., 2025¹⁵	0.604 (&)
		C	Visser et al., 2021¹⁸	0,65 (&)
		C	Efthymiadou et al., 2018¹⁹	0.56 (&)	62 (&)
		C	Claflin et al., 2023¹⁶	0.57 (&)
		C	Campbell et al., 2023¹⁷	0.52 (&)
Severe multiple Sclerosis	0.719	C	Young et al., 2025¹⁵	0.438 (&)
Moderate major depression	0.389	C	Franklin et al., 2021²⁰	0.730 (&)
Moderate major depression	0.389	C	Franklin et al., 2021²⁰	0.783 ($)
		C	Bilbao et al.2022²¹	0.560 (&)	46.85 (&)
		C	Assefa et al. 2025²²	0.457–0.546 (&)
Severe major depression	0.658	C	Assefa et al. 2025²²	0.214–0.332 (&)
		C	Claflin et al., 2023¹⁶	0.14 (&)
		C	Campbell et al., 2023¹⁷	0.18 (&)
Breast cancer, primary Phase	0.288	C	Rautalin et al., 2018²³	0.85 (&)	76.4 (&)
		C	Lidgren et al., 2007²⁴	0.696 (&)
		C	Lidgren et al., 2007²⁴	0.725 ($)
Breast cancer, metastatic Phase	0.451	C	Rautalin et al., 2018²³	0.74 (&)	66.2 (&)
		C	Rosenberg et al., 2022²⁵	0.83 ($)	85 ($)
		C	Lidgren et al., 2007²⁴	0.685 (&)
		C	Lidgren et al., 2007²⁴	0.725 ($)
		C	Ndirangu et al. 2024²⁶	0.65–0.77 (&)	63.4–70. 9 (&)
Breast cancer, terminal Phase	0.540	C	Rautalin et al., 2018²³	0.51 (&)	53.6 (&)
Lung cancer, primary Phase	0.288	C	Chouaid et al., 2013²⁷	0.71 (&)	69.3 (&)
		C	Iyer et al. 2013²⁸	0.63 (&)	60.8 (&)
Lung cancer, metastatic Phase	0.451	C	Chouaid et al, 2013²⁷	0.59 (&)	53.5 (&)
		C	Iyer et al. 2013²⁸	0.53 (&)	54.9 (&)
		C	Liao et al., 2024²⁹	0.81 ($)	70 ($)
Lung cancer, terminal Phase	0.540	C	Chouaid et al, 2013²⁷	0.46 (&)	48.2 (&)
Moderate rheumatoid arthritis	0.317	C	Gumber et al., 2025³⁰	0.8 ($)	93 ($)
		C	Frazzei et al., 2024³¹	0.64 (&)
		C	Haridoss et al., 2021³²	0.66 (&, pooled overall results of 31 studies)	61 (&, pooled overall results of 31 studies)
		C	Wan et al., 2024³³	0.586 (&)	47.3 (&)
		C	Efthymiadou et al., 2018¹⁹	0.58 (&)	66 (&)
Severe rheumatoid arthritis	0.581	C	Salaffi et al., 2011²⁴	0.473 (&)	53.7 (&)
Severe rheumatoid arthritis	0.581	C	Salaffi et al., 2011²⁴	0.465 ($)	55 ($)
End-stage renal disease on dialysis	0.571	C	Siriwardana et al., 2024³⁵	0.719 (&)	67.2 (&)
		C	Yang et al., 2019³⁶	0.622–0.864 (&)
SIH, our cohort	0.432	C		0.568 (&)	47.5 (&)	62.5 (&)
SIH, our cohort	0.432	C		0.655 ($)	45.5 ($)	65 ($)

Discussion

In this study, we provide the first patient data-derived estimate of a disability weight for persisting SIH. Using health-related quality of life data from the EQ-5D-5L instrument in a large, well-characterized cohort, we derived a mean disability weight of 0.432, indicating substantial non-fatal health loss associated with ongoing SIH. This estimate reflects the cumulative impact of SIH on daily functioning, headache, and psychological well-being during the symptomatic period prior to definitive treatment. By quantifying health loss associated with SIH on a numerical scale, our findings provide a metric that allows contextual interpretation alongside other neurological and pain-related conditions. However, a direct comparison of this newly estimated patient- and utility-based DW to the population-based health-state valuation surveys of the GBS studies is not appropriate. A direct comparison is only possible between the EQ-Index of 0.568 used to calculate the DW and previously catalogued EQ-Index scores of other chronic conditions, for example palliative breast cancer (EQ-Index 0.45), non-small cell lung cancer with severe adverse events (EQ-Index 0.45), or renal failure requiring hemodialysis (EQ-Index 0.44).³⁶

The disability attributed to SIH needs to be framed in the context of other pain-dominant, nonfatal neurological disorders that are already characterized within the Global Burden of Disease framework. Primary headache disorders, such as migraine, consistently rank among the leading causes of disability worldwide, with reported DWs of approximately 0.44 during the attacks.^17–20 These disability weights quantify health loss during discrete episodes and, thus, need to be interpreted within the frame of attack frequency and duration when estimating overall burden. In striking contrast, symptoms of SIH tend to be persistent or even near continuous prior to treatment, resulting in protracted functional impairment rather than episodic health loss.^2,3,7,10 Beyond headache intensity alone, disability in SIH seems to be further driven by a wider spectrum of symptoms that comprise functional limitation, fatigue, and psychological burden.^6,11 Put together, the estimated disability weight of 0.432 signifies a multidimensional and sustained loss of health in SIH, within the spectrum of chronic, non-fatal but highly disabling neurological disorders, and certain malignancies.

The disability associated with SIH also highlights a broader challenge in how neurological disease burden is conceptualized and quantified. Similar to other high-impact neurological and pain disorders, SIH predominantly affects previously healthy individuals in their working-age years, a demographic in which sustained disability carries severe personal and societal consequences.^1,7,23 However, SIH differs fundamentally from most primary headache disorders in its diagnostic trajectory. Multiple studies have demonstrated that SIH is frequently associated with substantial diagnostic delay, often extending over many months or even years, during which patients experience persistent symptoms and marked functional impairment.^7,21,37–39 This under-recognition is driven by multiple factors, including limited awareness of the condition, which contributes to delayed and missed diagnoses. Unlike episodic headache disorders, untreated SIH results in continuous health loss over prolonged periods, leading to a cumulative burden that is disproportionate to its relatively low incidence. This sustained health impact affects not only physical functioning but also mental well-being and socioeconomic participation, a dimension often not captured by burden-of-disease frameworks that prioritize predefined disease categories and prevalence estimates.^18,19 The absence of SIH as a distinct disease entity within the Global Burden of Disease classifications, and the lack of a disease-specific DW, therefore likely contributes to an underestimation of its true neurological burden. In this context, the derivation of a disease-specific DW for SIH represents a critical first step toward making the impact of spinal CSF leaks visible within established epidemiological and public-health frameworks.

Viewed from a public-health perspective, the present findings underscore that the impact of SIH extends beyond individual clinical encounters and has broader implications for the assessment of neurological disease burden. Although SIH is still considered a relatively rare condition, the combination of substantial pre-diagnosis and pre-treatment disability, prolonged diagnostic delay, and concentration in working-age adults suggests that its cumulative health impact is non-negligible. The new patient-derived disability weight of 0.432 provides a first quantitative expression of this impact. Importantly, for conditions such as SIH, where disability accrues over time rather than through recurrent acute events, even modest reductions in diagnostic delay may translate into meaningful reductions in population-level health loss.

Several strengths and limitations of the present study should be considered when interpreting these findings. Strengths include the large, well-characterized cohort of patients with confirmed SIH, the use of validated patient-reported outcome measures, and the focus on pre-treatment health status, which allowed estimation of disability during the untreated disease phase. The derivation of a DW directly from EQ-5D-5L data provides a transparent, reproducible and pragmatic approach that is particularly suitable for conditions not yet represented in the GBD framework.

Limitations include the single-center, tertiary-care design, which may limit generalizability and introduce referral bias toward more severe or complex cases. The derived disability weight therefore represents an average estimate of pre-treatment disability at the cohort level and does not account for interindividual variability or changes over time. EQ-Index values exhibited non-normality; however, with a sample size of 321, conclusions based on the mean disease weight seems justified because the central limit theorem ensures approximate normality of the sampling distribution of the mean, resulting in a rather valid standard error–based estimation. Moreover, the estimated DW was derived from patient-reported EQ-Index utilities (representing a pragmatic utility-derived approach) which is not conceptually equivalent to population-based health-state valuation surveys. Comparisons with official Global Burden of Disease disability weights must therefore be interpreted as contextual rather than methodologically equivalent. Furthermore, the present study focuses on deriving a disease-specific disability weight as a prerequisite for future DALY analyses that will incorporate disease duration and population-level epidemiological data.

Conclusion

In this study, we derived a patient- and utility-based estimate of disability associated with persisting spontaneous intracranial hypotension (SIH) using pre-treatment health-related quality of life data from a large cohort. The estimated disability weight (DW) of 0.432 indicates a substantial patient-reported health loss specific to SIH prior to definitive treatment. This patient-derived estimate may be used for comparison within other utility-based contexts, however, it should not be interpreted as comparable to GBD-derived DWs until further validation studies are available. These future studies should also include analyses incorporating incidence, disease duration, and treatment effects.

Article highlights

SIH is currently not represented in the Global burden of disease framework, and no disability weight (DW) is defined.

This study proposes a DW based on patient-derived quality of life data from a large cohort. The estimated DW of 0.432 indicates substantial health loss and provides a foundation for future burden-of-disease analyses.

Supplemental Material

sj-docx-1-cep-10.1177_03331024261444662 - Supplemental material for Toward quantifying disability in spontaneous intracranial hypotension: A patient-derived disability weight

Supplemental material, sj-docx-1-cep-10.1177_03331024261444662 for Toward quantifying disability in spontaneous intracranial hypotension: A patient-derived disability weight by Florian Volz, Mazin Omer, Manou Overstijns, Amir El Rahal, Marc Hohenhaus, Jan-Helge Klingler, Niklas Lützen, Horst Urbach, Charlotte Zander, Ian Carroll, Jürgen Beck and Katharina Wolf in Cephalalgia

Footnotes

Abbreviations

Acknowledgements

KW is fellow of the Margarete-von-Wrangell-Programm funded by the Ministry of Research, Science and Arts Baden-Württemberg. AER received a scholarship grant from the Michel et André Bouriez Foundation. HU is supported by the German Federal Ministry of Education and Research, received honoraria for lectures from Bayer, Biogen, GE, Eisai, Mbits, and Lilly, and he is coeditor of Clinical Neuroradiology. JHK received honoraria for lectures from B. Braun SE, AO Foundation, and Rimasys.

ORCID iDs

Florian Volz

Mazin Omer

Jürgen Beck

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Ethical considerations

Local Ethics Committee registration numbers: 24-1296-S1-retro, 24-1357-S1

Consent to participate

All patients consented to the publication of their demographic and PROM data.

Consent for publication

All authors have read and approved the manuscript and agree to the publication.

Author contributions

FV, MOm, KW, JB: Design of the study. FV, MOm, MOv, AER, KW: Data acquisition and analysis. JB, FV, HU, NL: Providing of infrastructure. Manuscript writing and corrections with contributions of all authors.

Declaration of conflicting interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Data availability statement

The study data are shared at reasonable request from other investigators.

Open practices

Not applicable.

Supplemental material

Supplemental material for this article is available online.

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