Neutrophil-to-lymphocyte ratio (nlr) as a predictor of endometriosis occurrence and prognosis: Evidence from a single-center study in Indonesia

Abstract

Intoduction

Endometriosis is a chronic inflammatory condition characterized by the presence of endometrial tissue outside the uterus, leading to pelvic pain and infertility. It affects approximately 10% of women of reproductive age. Endometriosis is associated with a chronic inflammatory process that results in pain, tissue remodelling, fibrosis, adhesions, and infertility. Numerous chronic inflammatory indicators can serve as practical prognostic and diagnostic biomarkers for the severity of the disease, one of which is the neutrophil-lymphocyte ratio (NLR). The normal range of NLR is 1–3, with mild stress falling within the range of 6–9, and critical conditions being indicated by values above 9.

Aim of study

This study aimed to investigate the association between endometriosis and the neutrophil-lymphocyte ratio (NLR).

Methods

The study was conducted at Margono Soekarjo General Hospital in Indonesia and involved all women who suspected endometriosis between January 2022 and May 2024. Several inclusion and exclusion criteria were applied. Statistical analysis was peformed to calculate the odds ratio.

Results

The study found that women with endometriosis had 4.80 times higher odds [OR 4.8, 95% CI, p = 0.001] of having an elevated NLR compared to those without endometriosis. This means that women with endometriosis have a 4.80 higher risk of having an elevated NLR compared to women without endometriosis.

Conclusions

There is a statistically significant association between endometriosis and NLR. NLR can serve as a biomarker with a potential role in the diagnosis and prognosis of endometriosis. Women with symptoms of endometriosis can undergo an NLR examination as a predictor or a pre-surgery assessment before confirmation through surgery and histopathological examination.

Keywords

endometriosis inflammation NLR predictor

Introduction

Endometriosis is a chronic, estrogen-dependent inflammatory disorder characterized by the ectopic growth of endometrial-like tissue outside the uterine cavity, most often involving the ovaries, peritoneum, and pelvic structures.¹ It is strongly associated with pelvic pain and infertility, making it a major cause of morbidity among women of reproductive age. The estimated global prevalence is 10–15%, although this number may be underestimated due to the high proportion of undiagnosed cases.1 In fact, many women with endometriosis remain asymptomatic for years, and the diagnosis is frequently delayed until they present with infertility or severe pelvic pain.² Clinical manifestations may vary widely; some women experience only mild discomfort, while others suffer from disabling pain and impaired fertility.

The clinical features of endometriosis are diverse and often nonspecific, which contributes to diagnostic challenges. The most commonly reported symptoms include abdominopelvic pain, dysmenorrhea, heavy or irregular menstrual bleeding, infertility, and dyspareunia.¹ Additional symptoms such as dyschezia, dysuria, chronic fatigue, and gastrointestinal complaints may also be present, further complicating differential diagnosis. Importantly, the severity of symptoms does not always correlate with the extent of disease, suggesting that underlying immune and inflammatory mechanisms play a critical role in symptom generation.^2,3

Although the precise cause of endometriosis remains elusive, several pathophysiological theories have been proposed to explain its development. The most widely accepted explanation is Sampson’s theory of retrograde menstruation, which describes the reflux of viable endometrial cells through the fallopian tubes into the peritoneal cavity during menstruation, where they implant and proliferate.^2,3 However, this mechanism alone does not account for all clinical presentations. Alternative hypotheses include the Müllerian remnant theory, which implicates embryonic tissue remnants that differentiate into endometrial-like lesions, and the vascular or lymphatic dissemination theory, which explains extrapelvic lesions through hematogenous or lymphatic spread. More recently, the stem cell theory has gained attention, suggesting that progenitor cells derived from bone marrow or the basal endometrium contribute to ectopic tissue formation. Despite decades of research, it is now widely accepted that the pathogenesis of endometriosis is multifactorial, involving a complex interplay of hormonal, immunological, genetic, and environmental factors.^1–3

Central to the disease process is the role of inflammation. In general, inflammation is a fundamental protective mechanism of the immune system, initiated as a vascular response to tissue injury or infection. It enables immune cells and soluble mediators to reach sites of injury, eliminate harmful stimuli, and initiate repair. In its acute form, inflammation is typically self-limiting, dominated by neutrophilic infiltration, edema, and rapid resolution. However, when the inciting factor persists, the inflammatory response becomes chronic, characterized by prolonged duration, mononuclear cell infiltration (lymphocytes and macrophages), angiogenesis, fibroblast activation, and tissue remodeling.⁴ The cardinal signs of inflammation (heat (calor), redness (rubor), swelling (tumor), pain (dolor), and functional loss (functio laesa)) reflect these processes.⁴

In endometriosis, the persistence of ectopic endometrial tissue creates a state of sustained chronic inflammation. Ectopic implants release pro-inflammatory cytokines and growth factors, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α), which recruit and activate macrophages and neutrophils. These immune cells release reactive oxygen species (ROS), proteolytic enzymes, and angiogenic factors, fostering tissue damage, neovascularization, and lesion survival. In addition, impaired apoptosis and defective immune clearance allow ectopic endometrial cells to persist in the peritoneal cavity. Collectively, these mechanisms establish a self-perpetuating inflammatory microenvironment, which contributes to pain, infertility, and progression of disease.^3,4

Given this inflammatory basis, hematological markers of systemic inflammation have been increasingly investigated in endometriosis. One such marker is the neutrophil-to-lymphocyte ratio (NLR), derived from routine complete blood counts. Elevated neutrophils indicate systemic inflammatory activation, whereas reduced lymphocyte counts reflect relative immunosuppression and stress. NLR therefore integrates both arms of the immune response, serving as a sensitive marker of systemic inflammation.⁵ Its clinical utility lies in its simplicity, cost-effectiveness, and reproducibility compared to other specialized inflammatory assays.^2,5

The normal physiological range for NLR is generally 1–3. An NLR of 4–6 is indicative of mild systemic stress, 7–9 suggests moderate stress, and values above 9 are typically associated with severe inflammatory or critical conditions.⁶ Elevated NLR has been linked to poor outcomes in cardiovascular disease, malignancies, and autoimmune disorders. In gynecology, it has shown promise in conditions such as ovarian cancer, polycystic ovary syndrome (PCOS), and more recently, endometriosis. Because endometriosis represents a chronic inflammatory state, NLR has the potential to serve not only as a diagnostic marker but also as a prognostic indicator and a non-invasive tool for disease monitoring.

At present, diagnostic laparoscopy remains the gold standard for confirming endometriosis. While highly accurate, it is invasive, resource-intensive, and not feasible as a screening tool in routine clinical practice. Therefore, identifying noninvasive, accessible biomarkers such as NLR may improve early detection and reduce diagnostic delays. Investigating the association between NLR and endometriosis could thus provide important clinical value, paving the way for a simple, widely applicable diagnostic adjunct in women with suspected disease.

This study aimed to evaluate the relationship between endometriosis and neutrophil-to-lymphocyte ratio (NLR), thereby exploring its potential role as a practical and cost-effective biomarker in this chronic inflammatory condition.

Materials and methods

Study design and setting

This was a hospital-based cross-sectional study conducted between January 2022 and May 2024 at General Hospital Prof. Dr. Margono Soekarjo (RSMS), Purwokerto, Indonesia, a tertiary referral center providing comprehensive gynecological services. All procedures were carried out in accordance with relevant guidelines and regulations of Local Institutional Review Board of RSMS (Reference Number: 420/05073).

Study population

The study population comprised women attending the gynecology outpatient clinic with clinical suspicion of endometriosis. Initial evaluation included a structured interview to assess symptomatology, focusing on abdominopelvic pain, dysmenorrhea, menorrhagia, infertility, and dyspareunia. Physical examination was performed to detect tenderness or nodularity suggestive of endometriotic lesions, followed by gynecological examination and transvaginal or transabdominal ultrasonography (USG) to identify adnexal masses or other features consistent with endometriosis.

All participants subsequently underwent diagnostic laparoscopy as part of routine clinical management. Histopathological examination of tissue samples obtained during laparoscopy served as the reference standard for definitive diagnosis. Based on histopathological confirmation, participants were assigned to the case group (endometriosis-positive) or the control group (endometriosis-negative). The case group are those who confirmed as endometriosis patients by histopathological examinations, while the control group are those with similar symptoms but confirmed as non-endometriosis patients by histopathological patients.

Data collection and variables

Preoperative complete blood counts were retrieved from hospital medical records as part of the standard presurgical work-up. The primary variable of interest was the neutrophil-to-lymphocyte ratio (NLR), calculated as the absolute neutrophil count divided by the absolute lymphocyte count.

For descriptive purposes, NLR values were classified according to established thresholds⁶:

• Normal: 1–3

• Mild stress inflammation: 4–6

• Mild-to-moderate stress inflammation: 7–9

• Critical condition: >9

For the purposes of statistical analysis in this study, NLR was dichotomized into two groups:

• Low NLR group: 1–3

• High NLR group: >3

Exclusion criteria

Patients were excluded if they had a history of chronic inflammatory conditions such as chronic obstructive pulmonary disease, rheumatoid arthritis, or inflammatory bowel disease, or if they had a history of malignancy. In addition, women with incomplete clinical or laboratory data, particularly missing preoperative NLR measurements or unavailable histopathological results, were not included in the analysis (Figure 1).

Figure 1.

Flowchart of subject selection.

Sample size estimation

This study employed a consecutive sampling approach, including all eligible patients presenting to the gynecology clinic of General Hospital Prof. Dr. Margono Soekarjo (RSMS) between January 2022 and May 2024.

n = {[\frac{Z α \sqrt{2 V 1} + Z β \sqrt{V 1 + V 2}}{A U C 1 - A U C 2}]}^{2}

n = {[\frac{1, 96 \sqrt{2 X 0, 153} + 1, 64 \sqrt{0, 153 + 0, 098}}{0, 6 - 0, 8}]}^{2}

n = 90, 57 = 91

= 91 + (10 % d r o p o u t)

n = 100 patients

After applying the exclusion criteria, a total of 100 patients were included in the final analysis. The association between endometriosis and neutrophil-to-lymphocyte ratio (NLR) was assessed using the odds ratio (OR), while statistical significance was evaluated using the Chi-square test. All statistical analyses were conducted with IBM SPSS Statistics version 29.0.1.0 (IBM Corp., Armonk, NY, USA).

Data collection

Data were obtained from women who presented to the gynecology clinic of RSMS during the study period (January 2022–May 2024). Clinical information, imaging findings, histopathological results, and preoperative hematological parameters, including neutrophil and lymphocyte counts, were extracted from patient medical records. The NLR was calculated for each participant, and additional demographic and clinical variables were recorded for analysis.

Statistical analysis

Univariate analysis was performed to describe both dependent and independent variables, providing a foundational understanding to support further bivariate analysis. This analysis was also used to characterize the demographic and clinical status of patients included in the study. For categorical variables, univariate analysis was presented descriptively in terms of proportions.

For numerical data, normality was assessed using the shapiro wilk test for sample sizes less than 50, and the Kolmogorov-smirnov test for sample sizes greater than 50. Comparative statistical analysis between two groups was conducted using the independent t-test for normally distributed data, and the Mann-Whitney test as a non-parametric alternative for non-normally distributed data.

Categorical variables were analyzed using the Chi-square test, provided that its assumptions were met (i.e., no more than 20% of expected cell counts were less than 5). If these assumptions were violated, the Fisher’s exact test was applied for 2×2 contingency tables, while the Kolmogorov–Smirnov test was used for larger tables. Statistical significance was determined based on p-values, with p ≤ 0.05 considered statistically significant and p > 0.05 considered not statistically significant. All collected data were recorded using standardized forms and analyzed using SPSS version 26.0 for Windows.

Following bivariate analysis, further evaluation was conducted to determine significant differences between predicted outcomes based on the Receiver Operating Characteristic (ROC) curve cut-off values and observed mortality outcomes. Model calibration was assessed using calibration curves and the Hosmer–Lemeshow goodness-of-fit test.

Likelihood ratios were also calculated as an alternative measure of diagnostic accuracy. Adjustments to the cut-off point of a diagnostic test influence its sensitivity and specificity, and these changes are graphically represented using the ROC curve. Finally, binary logistic regression analysis was performed to assess the accuracy of predictors, as the dependent variable was binary in nature. Statistical significance in this analysis was also determined using a threshold of p ≤ 0.05.

Results

This study included a total of 100 subjects, consisting of 50 women with histopathologically confirmed endometriosis (case group) and 50 women without endometriosis (control group). The age distribution showed that women with endometriosis were more frequently represented in the 36–45-year age group, whereas fewer cases were observed in the <25 years and >56 years age groups (Table 1).

Table 1.

Patient characteristics.

Patient characteristics		Endometriosis (n=50) (%)	Non-endometriosis (n=50) (%)	p-value
Ages				0.022*
Mean±Std		41.40±10.782	46.72±12.105
Median		42.00	46
Range (min-max)		18.0-74.0	20,0-72.0
	≤ 25	3 (6)	3 (6)
	26-35	10 (20)	3 (6)
	36-45	21 (42)	16 (32)
	46-55	13 (26)	19 (38)
	>56	3 (6)	9 (18)
NLR				0.035*
	Mean±Std	7,90±10,795	4,61±5,791
	Median	4,66	2,73
	Range (min-max)	1,20-69,40	1,31-29,54
	Low/Normal (1-3)	21 (42)	39 (78)
	High (>3)	29 (58)	11 (22)
BMI				0.983
	Mean±Std	24,06±4,447	24,46±5,199
	Median	23,90	23,22
	Range (min-max)	15,52-35,10	16,00-38,30
Parity				0.050
	Mean±Std	1,28±1,499	2,00±1,863
	Median	1,00	2,00
	Range (min-max)	0,00-5,00	0,00-7,00

*Notes: NLR neutrophil-lymphocyte ratio.

Analysis of the neutrophil-to-lymphocyte ratio (NLR) revealed that women with endometriosis had a higher proportion of elevated NLR values compared with women in the control group. This finding suggests a potential association between chronic inflammation, as reflected by increased NLR, and the presence of endometriosis. Independent t-test was used for numerical data with normal distribution (age) and an alternative analysis such as Mann Whitney test for abnormal data distribution were found in BMI and parity. We earned p-value >0.05 in BMI and parity that shows no significant difference were found between BMI and parity for both endometriosis and non-endometriosis group.

Table 2 presents the association between endometriosis and neutrophil-to-lymphocyte ratio (NLR). The analysis demonstrated a significant relationship, with an odds ratio (OR) of 4.80 (95% CI: 2.044–11.728, p = 0.001). This indicates that women with endometriosis were approximately 4.8 times more likely to have an elevated NLR compared with women without endometriosis. The p value of 0.001, which is below the conventional threshold of 0.05, confirms that the observed association is statistically significant. This association will be the potential of NLR as a predictor for endometriosis cases occurances Figure 2.

Table 2.

Crude odd from univariate analysis, p-value by chi-square, and confidence interval.

Disease	Endometriosis (n=50)	Non-endometriosis(n=50)	Odd ratio	p value	Confidence interval 95%
High NLR (n=40)	29	11	4.80	0.001	2.044-11.728
Low NLR (n=60)	21	39	4.80	0.001	2.044-11.728

*Notes: NLR neutrophil-lymphocyte ratio.

Figure 2.

ROC curve of NLR diagnostic ability.

Table 3 shown the analysis for sample using Chi Square. NLR cut off was shown to be significant statistically as there were significant proportion difference statistically between NLR cut off value in both endometriosis and non-endometriosis group. Sensitivity value of 58% present statistically weak sensitivity, however 78% specifity is considered moderately strong statistically. The positive predictive value of NLR cutoff is 72.5% showed moderate strength statistically, while negative predictive value of 65% was considered weak in this diagnostic test. The accuracy value of 68% showed a weak correlation statistically.

Table 3.

The correlation between NLR cutoff and endometriosis status.

Disease	Endometriosis (n=50)	Non-endometriosis(n=50)	Sensitivity (%)	Specifity (%)	p value	AUC (%)
High NLR (n=40)	29 (58)	11 (22)	58	78	0.0001 *	62.3
Low NLR (n=60)	21 (42)	39 (78)	58		0.0001 *	62.3

*Notes: p-value of categoric data were counted based on Chi-square test with Kolmogorov Smirnov and Fisher’s Exact if Chi-square conditions were not met. Significance value based on p<0.05.

The ROC curve showed that NLR have a good diagnostic power with AUC of 62.3% meaning NLR can be used to predict endometriosis accurately in 62 out of 100 patients. NLR stand on 52% to 71.8% level based on confidence interval and was proven statistically significance. The NLR cut off point used in this study was NLR of 3 with sensitivity of 58% and specifity of 78%, meaning that 62.3% patients with NLR value >3 were predicted to experience endometriosis.

Table 4 shown that BMI cutoff is not significant statistically towards endometriosis incidence as there were no significant proportional difference for both groups. However, we found that NLR, age, and parity cutoff have p-value <0.05 which means statistically significant as there were significant proportion difference statistically for both groups.

Table 4.

Comparison of NLR, age, BMI, and parity cutoff based on endometriosis status.

Variabel	Status		Nilai P
Variabel	Endometriosis N=50	Non-EndometriosisN=50	Nilai P
NLR			0,0001**
>3	29(58,0%)	11(22,0%)
<3	21(42,0%)	39(78,0%)
Usia			0,016 *
≥45 tahun	34(68,0%)	22(44,0%)
<45 tahun	16(32,0%)	28(56,0%)
BMI			0,221
>25.08	23(46,0%)	17(34,0%)
<25.08	27(54,0%)	33(66,0%)
Paritas			0,009 *
≤1	34(68,0%)	21(42,0%)
>1	16(32,0%)	29(58,0%)

*Notes: Chi-square analysis with alternative of Kolmogorov Smirnov and fisher’s exact test was used to analyze categoric data.

Table 5 present the correlation between multiple independent variables with endometriosis incidences (NLR, age, BMI, and parity). Variable with p-value <0.25 in bivariate analysis were included in order to analyse which variable dominantly affect the endometriosis incidences. This study found that not all variables simultaneously have significant effect on endometriosis. The final model showed that the variable with most effect on endometriosis incidence is NLR and parity (p<0.05). Thus, we can conclude that NLR and parity hold strong correlation in predicting endometriosis incidences.

Table 5.

Binary logistic regression analysis.

		B	S.E.	Nilai P	OR	Or CI 95%
		B	S.E.	Nilai P	OR	Lower	Upper
Crude model	1. NLR cutoff	1,869	0,506	<0,001	6,484	2,406	17,477
	2. Age Cutoff	0,235	0,544	0,666	1,265	0,435	3,676
	3. BMI Cutoff	0,891	0,492	0,070	2,437	0,930	6,386
	4. Parity Cutoff	1,448	0,586	0,014	4,253	1,348	13,415

Final Model	1. NLR Cutoff	1,900	0,502	<0,001	6,685	2,498	17,894
	2. BMI Cutoff	0,915	0,488	0,060	2,497	0,960	6,494
	3. Parity Cutoff	1,578	0,505	0,002	4,846	1,802	13,031

*Notes: Independent variables included in the model are those with p-value <0.25 in bivariate analysis.

Discussion

Endometriosis is a gynecological disorder that most commonly occurs in women of reproductive age, particularly between 25 and 35 years. Interestingly, in this study, the highest prevalence of endometriosis was observed in women aged 36–45 years. According to the Indonesian Ministry of Health Age Category Guidelines (2009), this group is categorized as late adulthood. These findings are consistent with the study by Christ et al., which reported that the incidence of endometriosis in the United States was also highest among women aged 36–45 years.⁷ This phenomenon may reflect a diagnostic delay, where women experience symptoms for years before a definitive diagnosis is established.⁸ The average delay is often estimated from the onset of initial symptoms to the time of diagnosis. Several factors contribute to this delay, including patient-related issues (such as age at first symptoms, normalization of pain, delayed health-seeking behavior, age at menarche, menstrual cycle length, duration of menstrual flow, parity, and use of oral contraceptives) and physician-related issues (such as under-recognition of symptoms or misattribution to other gynecologic conditions).^9–12

Early menarche increases lifetime estrogen exposure, thereby elevating the risk of endometriosis. Similarly, shorter menstrual cycles and prolonged menstrual flow can increase retrograde menstruation and estrogen exposure, both of which enhance the likelihood of developing endometriosis. Conversely, higher parity has been shown to lower the risk, likely because pregnancy induces prolonged periods of elevated progesterone levels, which may suppress the establishment or growth of endometriotic lesions. Moreover, combined oral contraceptives, by reducing the volume of menstrual bleeding, may also decrease the risk or progression of endometriosis.^10–12

Endometriosis is characterized as a chronic inflammatory disorder, largely sustained by immune system dysregulation. Women with endometriosis often have elevated concentrations of activated peritoneal macrophages, which promote angiogenesis by secreting vascular endothelial growth factor (VEGF) and other trophic factors that facilitate the growth of endometriotic lesions. These macrophages also release pro-inflammatory mediators, including tumor necrosis factor-α (TNF-α), interleukins, and other cytokines, all of which contribute to cell proliferation, invasion, and implantation of ectopic endometrial tissue. As a result, both acute and chronic inflammatory pathways are activated, leading to changes in immune cell populations such as neutrophils and lymphocytes.^13,14

The findings of this study align with this pathophysiological mechanism. The neutrophil-to-lymphocyte ratio (NLR), a systemic marker of inflammation, was significantly higher in women with endometriosis. In this study, 58% of patients with endometriosis had an elevated NLR (≥3), and women with endometriosis had a 4.8-fold higher risk of elevated NLR compared with women without endometriosis (OR 4.80, 95% CI 2.044–11.728, p = 0.001). This finding is consistent with previous reports. Cho et al. (2008)¹⁵ demonstrated that patients with advanced-stage endometriosis had significantly higher NLR values compared to healthy controls, supporting the role of NLR as a non-invasive inflammatory marker. Similarly, Tokmak et al. (2016)¹⁶ found that NLR was significantly elevated in women with endometriomas compared to those with benign ovarian cysts, suggesting that NLR may assist in differentiating endometriosis from other gynecologic conditions. More recently, Tabatabaei (2023)¹⁷ confirmed that an elevated NLR correlates with disease severity and chronic pelvic pain, further highlighting its potential prognostic value.

Sometimes, endometriosis expand towards the ovaries. Endometriosis involving the ovaries can lead to the formation of endometriomas, which may compromise ovarian function through space-occupying effects and local inflammatory responses, thereby reducing the amount of functional ovarian tissue. This impairment may be further exacerbated by surgical intervention, as operative management can inadvertently damage an already compromised ovarian reserve. Although the natural age-related decline in ovarian follicles typically does not markedly affect fertility before the age of 37, ovarian endometriosis may accelerate this decline, leading to an earlier reduction in reproductive potential. Consequently, the concept of ovarian reserve has become central in evaluating fertility, referring to the remaining quantity of ovarian follicles as a predictor of fecundity. Assessment of ovarian reserve is commonly performed day-3 follicle-stimulating hormone (FSH) levels and antral follicle count (AFC) via ultrasound, while anti-Müllerian hormone (AMH), produced by preantral and growing follicles, has emerged as a reliable marker due to its stability across the menstrual cycle and independence from hormonal treatments. Notably, AMH levels are often reduced in infertile women with endometriosis, reflecting diminished follicular quantity.¹⁸

Recent evidence further highlights the role of systemic inflammation in the pathophysiology of endometriosis and its impact on ovarian reserve. Inflammatory indices such as the platelet-to-lymphocyte ratio (PLR) and other composite markers have been shown to correlate not only with the presence of endometriosis but also to independently predict reduced ovarian reserve, as reflected by lower AMH levels. This suggests that chronic inflammation may adversely affect the ovarian microenvironment through mechanisms such as oxidative stress, cytokine-mediated damage, and impaired folliculogenesis, ultimately contributing to diminished ovarian function.¹⁹

Unlike age-related follicular decline, which is associated with reduced oocyte quality in women over 40 years, decreased ovarian reserve in younger women with endometriosis does not appear to significantly impair oocyte quality. Although some studies suggest reduced fertilization rates in affected women, evidence from assisted reproductive technology (ART) indicates that the overall impact of endometriosis on oocyte quality is likely minimal, as pregnancy rates remain relatively preserved even among those with a poor ovarian response.¹⁸

The elevated NLR in endometriosis reflects the interplay of immune dysregulation and chronic inflammation. Neutrophilia in these patients is thought to arise from increased cytokine signaling (e.g., IL-6, TNF-α) that stimulates neutrophil activation, while relative lymphopenia may reflect an exhausted or suppressed adaptive immune response. Together, these changes result in an increased NLR, mirroring the systemic inflammatory burden. Therefore, NLR could represent not only a diagnostic clue but also a marker of disease activity and severity^.20–22

Limitations

This study has several limitations. First, detailed reproductive and menstrual history, such as age at menarche, menstrual cycle length, duration of flow, parity, and contraceptive use, was not collected, which may have provided additional insight into risk factors and disease characteristics. Second, the cross-sectional design restricts causal inference, and longitudinal follow-up would be valuable to clarify whether elevated NLR predicts disease progression or treatment response. Third, the study was conducted in a single center with a relatively limited sample size, which may affect the generalizability of the findings. Future research should include multicenter cohorts with larger populations, integrate comprehensive reproductive data, and explore the role of NLR in monitoring disease severity and response to therapy.

Conclusion

This study demonstrates a statistically significant association between NLR and endometriosis, with women affected by endometriosis being 4.8 times more likely to exhibit elevated NLR compared to those without the disease. Based on this local dataset, NLR shows potential as a predictive marker and may be considered as part of the preoperative assessment in women with suspected endometriosis, although confirmation through surgery and histopathological examination remains essential.

Footnotes

ORCID iDs

Ruswana Anwar

Dina Marlina

Aditya Utomo

Edy Priyanto

Megawati Albadly Ponco Dewi Poernomo

Ethical considerations

The study obtained an approval from the Research Ethics Committee of Margono Hospital, Purwokerto, Indonesia (Approval No. 420/05073). All patients in this study were examined, and the ethical standards set out in the 1964 Declaration of Helsinki were adhered to.

Consent to participate

Written informed consent for publication and any accompanying images was obtained from the patient or their legally authorized representative in the case of participants with no formal education or considered minors. All patients, or the legally authorized representatives have signed informed consent to publish their medical information and/or images in the manuscript.

Consent for publication

Written informed consent was obtained from all participants or their legally authorized representatives prior to study enrolment, including consent for the use and publication of anonymized clinical data. No personally identifiable information is included in this article.

Author contributions

R.A., R.R., D.M., and A.U. did the conception of the study and revised the manuscript critically for important intellectual content. R.R. did the acquisition of data, analysis, and interpretation of the data. R.R., D.M., A.U., A.D.N., W.C., and M.A.P.D.P drafted the manuscript, and revised the manuscript. A.D.N., M.A.A., E.P. supervised the study and manuscript critically for important intellectual content. All of the authors have read and approved the final manuscript as it has been submitted and agree to be accountable for all aspects of the work.

Funding

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

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 data supporting this study’s findings are available from the corresponding author upon reasonable request. The data are not publicly available due to privacy or ethical restrictions.*

Disclosure statement

The authors report no potential conflicts of interest was reported by the authors. All authors have approved the final version of the manuscript for publication. All authors agree to be accountable for all aspects of this study.

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