Cholecystectomy or non-operative management for cholecystitis in elderly patients: An analysis based on hospital practice patterns

Abstract

Background and Aims:

Early cholecystectomy improves outcomes in acute cholecystitis, yet surgeons often hesitate to operate on elderly and multimorbid patients, and prospective data in this group are lacking. This cohort study compared outcomes across hospitals with differing operative policies to estimate the effect of surgery among the elderly.

Methods:

Retrospective data using the Swedish National Inpatient Register, including 12,481 patients aged ⩾ 70 years treated for cholecystitis between 2015 and 2019, were analyzed. Outcomes included all-cause and gallstone-related mortality, length of stay related to gallstone disease during the index admission, and within 1 and 3 years. Hospitals and counties were categorized into quartiles based on cholecystectomy rates (Q1 = lowest, Q4 = highest). Survival was assessed using Cox proportional hazards regression. Length of stay was analyzed with linear regression.

Results:

Patients treated at Q1 hospitals were slightly older but had similar comorbidity burdens compared to Q4 hospitals. Surgical rates ranged from 25% to 60%. Overall mortality was lower in Q4 counties, but not significantly different at hospital level (hazard ratio (HR) = 0.86 95% confidence interval (CI) = 0.77–0.96). Gallstone-related mortality did not differ across quartiles. Although the index admission length of stay was similar, cumulative length of stay at 1 and 3 years was shorter for patients treated at Q4 hospitals compared to Q1 (0.87 fewer days at 3 years; 95% CI = 0.39–1.34).

Conclusions:

Hospitals with higher cholecystectomy rates did not demonstrate lower mortality, but regions with higher surgical rates showed improved survival. Higher operative rates were associated with fewer recurrences and reduced cumulative length of stay, suggesting that increased use of cholecystectomy benefits both patients and healthcare systems.

Clinical trial registration:

Not applicable.

Keywords

Registry hospital policy survival length of stay

Context and relevance

Early cholecystectomy is often considered less beneficial for elderly, comorbid or frail patients with acute cholecystitis, and conducting randomized trials in this population is challenging.

In this study, we examined patients aged ⩾ 70 years by exploiting the naturally low variation in age and comorbidity across large Swedish regions. The proportion of patients undergoing cholecystectomy at each hospital (ranging from 17% to 73%) was used as the exposure. Although survival did not differ between hospitals with low and high surgical rates, patients treated at hospitals with higher surgical rates experienced fewer recurrences and shorter cumulative length of stay during 3 years of follow-up.

Cholecystectomy is safe and beneficial even in patients over 70 years of age, including in settings where surgery is offered to a broad majority of patients.

Background

Acute cholecystitis is a common complication of cholecystolithiasis. Early cholecystectomy is the standard treatment, as it resolves the acute condition and prevents recurrent gallstone-related complications.^1,2 In elderly or comorbid patients, initial non-operative management may be considered, sometimes followed by elective surgery. However, delaying surgery increases the risk of recurrence,³ and approximately 30%–40% of patients experience recurrent episodes if surgery is not performed.⁴–⁸ Studies of early surgery have demonstrated reduced mortality and healthcare costs,^7,9 yet it is not always offered to older or multimorbid patients.⁵ Given evidence suggesting an acceptable risk of severe postoperative complications and mortality even in high-risk groups, early surgery may be appropriate for more patients when their recurrence risk is sufficiently high.^4,10,11

Randomized trials in this population are difficult to conduct due to challenges in enrolling elderly and frail patients. Although small randomized trials suggest that surgery as a viable option,¹² retrospective studies remain inherently biased because patients selected for surgery are typically healthier.

The overall health and age distribution of the Swedish population are relatively uniform across larger geographical areas.^13,14 These regions are generally served by one or a few hospitals, and patients are assigned to hospitals based on residence rather than on personal preference. Consequently, variation in surgical treatment rates for cholecystitis is largely driven by hospital policy rather than patient characteristics such as age or comorbidities.

Some patients are clearly suitable candidates for surgery, whereas others are clearly unsuitable due to frailty or other conditions. Between these groups lies an intermediate-risk population for whom the likelihood of undergoing surgery depends on hospital policy (Fig. 1). Differences in outcomes within this group can therefore serve as a proxy for the effect of surgical treatment.

Fig. 1.

Principle of using hospital policy as the instrumental variable.

This study aimed to compare mortality among patients aged 70 years and older with a first-time episode of acute cholecystitis treated at hospitals with high versus low surgical rates. We also examined initial hospital length of stay (LoS) and the number of days patients were readmitted for gallstone-related or surgical complications within 3 years.

Methods

The study was approved by the Swedish Ethics Review Authority (dnr 2022-06449-01 and 2023-01971-01). The manuscript was prepared according to the STROBE guidelines.¹⁵

Material

This was a retrospective registry-based cohort study. Data were obtained from the National Board of Health and Welfare’s National Patient Register (NPR), which contains diagnostic and surgical codes for nearly all hospitalizations since 1987 and secondary care outpatient visits since 2001.¹⁶

Patients aged ⩾ 70 with a first-time diagnosis of cholecystitis (using ICD-10-SE, K80.0, K80.1, K81.0) between 2015 and 2019 were included. Cholecystectomies were identified using NOMESCO¹⁷ procedure codes JKA20 and JKA21. Individuals with prior cholecystectomy, ERCP, or gallstone-related complications before 2015 were excluded.

For included patients, all inpatient and outpatient NPR records were used to calculate the Charlson Comorbidity Index (CCI) at the time of the index event (first cholecystitis).^18,19 Follow-up continued until 31 December 2022, with mortality data obtained from the National Cause of Death Register.

Data preparation

The exposure of interest was treatment at a hospital with a high proportion of early cholecystectomies, defined as surgery within 10 days of diagnosis. Hospitals treating more than 100 patients were identified individually; smaller hospitals were grouped under “other.” For each hospital, the proportion of patients aged ⩾ 70 years undergoing early cholecystectomy was calculated and categorized into quartiles (Q1 = lowest, Q4 = highest). For sensitivity analyses, hospitals were further divided into deciles: decile 1 (lowest surgical rate), decile 10 (highest), and deciles 2–9 combined as “Middle.” Patients were also grouped by Sweden’s 21 healthcare regions, and regional surgical proportions were categorized into quartiles. Patients ⩾ 80 years were identified for subgroup analysis.

Outcomes included all-cause mortality, gallstone-related mortality, LoS during the index admission, and cumulative LoS for any readmission related to gallstone disease or surgical complications within 1 and 3 years of the index event.

The index event was defined as the first hospitalization with cholecystitis during the study period. Time to death or end of follow-up was calculated from the admission date. Cause of death was considered gallstone-related if any ICD-10-SE codes K80–K85 appeared among listed causes, or if cholecystectomy occurred within 4 weeks of death. LoS was calculated using admission and discharge dates from all NPR inpatient episodes with a K80–85 code within 3 years of the index event.

Statistical analysis

No power analysis was performed as all eligible patients were included. Missing data were not imputed. A direct acyclic graph illustrating assumed causal relationships is provided in Fig. 1.

Patient and hospital characteristics were compared across quartiles using the chi-square test for categorical variables and the Kruskal-Wallis test for continuous variables. The Dunn test was used for post-hoc comparisons. Differences in LoS between Q1 and Q4 hospitals linear regressions adjusted for age were fitted. Survival differences were visualized with Kaplan-Meier curves. Cox proportional hazards regression was used to estimate hazard ratios (HR) adjusting for age and comorbidity (CCI). Subgroup analyses were performed for patients aged ⩾ 80 years. Gallstone-related and surgical mortality were analyzed using Cox regression across hospital quartiles. Further sensitivity analyses included comparisons between the lowest and highest hospital deciles and analyses using regional surgical proportions as the exposure. All statistical analyses were conducted using R version 4.4.3 and RStudio 2024.12.1.

Results

There were 12,481 patients aged ⩾ 70 years treated for cholecystitis in Sweden between 2015 and 2019. Of these, 4806 (39%) underwent cholecystectomy within 10 days of the index event. The mean follow-up for surviving patients was 5.2 years. Surgical rates varied across hospitals: in the lowest quartile (Q1), 17%–30% of patients had early surgery, whereas in the highest quartile (Q4), 48%–73% underwent surgery (Table 1). Patients treated at Q1 hospitals were older than those at Q4 hospitals (p = 0.007), but there were no significant differences in sex or comorbidity burden (CCI). Notably, patients in Q3 has higher comorbidity scores compared with Q1, Q2, and Q4 (p = 0.004, 0.04, 0.02, respectively). Recurrent gallstone-related complications occurred in 32% of patients at Q1 hospitals and 21% at Q4 hospitals. Supplementary Table 1 presents data from the 44 largest hospitals, showing surgical proportions ranging from 17% to 73%, along with mean age, sex distribution, weighted CCI, and 1-year mortality. The proportion of delayed surgery did not differ across quartiles; in total, 568 (4.6%) patients underwent delayed cholecystectomy. Cholecystostomy was performed in 435 patients, of whom 426(5.1%) were among the 8355 patients who did not undergo surgery.

Table 1.

Demographics of patients by hospital quartile for patients with cholecystitis between 2015 and 2019 in Sweden.

Characteristic	Overall	Q1	Q2	Q3	Q4	p-value^b
Characteristic	N = 12,481	N = 3093	N = 2925	N = 4176	N = 2287	p-value^b
Age (years)^a	78 (73, 84)	78 (73, 84)	78 (73, 84)	78 (73, 84)	78 (73, 83)	0.028
Sex						0.12
Male	6631 (53%)	1688 (55%)	1518 (52%)	2190 (52%)	1235 (54%)
Female	5850 (47%)	1405 (45%)	1407 (48%)	1986 (48%)	1052 (46%)
CCI (weighted)	2 (0, 3)	2 (0, 3)	2 (0, 3)	2 (0, 3)	2 (0, 3)	< 0.001
Unknown	2	1	0	1	0
Early Surgery	4806 (39%)	768 (25%)	956 (33%)	1701 (41%)	1381 (60%)	< 0.001
LoS (days)^a	4 (2, 7)	4 (3, 7)	4 (3, 7)	4 (2, 7)	4 (3, 7)	0.002
LoS 1 year (days)^a	5 (3, 10)	5 (3, 9)	5 (3, 10)	6 (3, 10)	5 (3, 9)	< 0.001
LoS 3 years (days)^a	6 (3, 10)	6 (3, 10)	6 (3, 11)	6 (3, 11)	5 (3, 9)	< 0.001
Recurrence						< 0.001
None	8719 (70%)	2103 (68%)	2002 (68%)	2801 (67%)	1813 (79%)
Cholecystitis	2770 (22%)	711 (23%)	714 (24%)	1036 (25%)	309 (14%)
Pancreatitis	447 (3.6%)	126 (4.1%)	107 (3.7%)	149 (3.6%)	65 (2.8%)
Cholangitis	545 (4.4%)	153 (4.9%)	102 (3.5%)	190 (4.5%)	100 (4.4%)
30-day Mortality	519 (4.2%)	134 (4.3%)	124 (4.2%)	181 (4.3%)	80 (3.5%)	0.4
Unknown	19	1	7	7	4
1-year Mortality	1637 (13%)	430 (14%)	388 (13%)	562 (13%)	257 (11%)	0.027
Unknown	19	1	7	7	4

Median (Q1, Q3); n (%). ^bKruskal–Wallis rank-sum test and Pearson’s chi-square test were used to test for between-group differences. CCI: Charlson Comorbidity Index; LoS: length of stay.

Supplementary Table 2 summarizes characteristics by hospital deciles. Patients treated at top-decile hospitals were younger (p = 0.02) but did not differ in comorbidity burden compared with patients at bottom-decile hospitals. Supplementary Tables 3 and 4 present data by county, where early surgical proportions ranged between 21% and 59%. In counties within the highest quartile of surgery (Q4), 55% of patients underwent early cholecystectomy. These patients were younger (Q4 vs Q1 p = 0.02) and had fewer recurrences, with no difference in mortality.

Analysis of length of stay

Initial LoS differed significantly across hospital quartiles (Table 1). However, direct comparison of Q1 versus Q4 showed no difference after adjusting for age and comorbidity (Table 2, p = 0.8). When cumulative LoS was assessed over 1 and 3 years, patients treated at Q4 hospitals had significantly shorter LoS than those treated at Q1 hospitals (p = 0.002 and p < 0.001). At 1 year, LoS was 0.71 days shorter (95% CI = 0.26–1.15), and at 3 years, 0.87 days shorter (95% CI = 0.39–1.34) for Q4 hospitals.

Table 2.

Length of stay for patients over 70 years old with cholecystitis in Sweden 2015–2019. Linear regression with adjustment for differences between hospitals and counties.

	Covariate	Quartiles by hospital		Quartiles by county
	Covariate	Estimate (95% CI)	p	Estimate (95% CI)	p
LoS index	Intercept	−1.74 (−3.04 to −0.43)	0.00936	−1.87 (−3.19 to −0.56)	0.00529
	Q2 vs Q1	0.25 (−0.07 to 0.57)	0.11976	0.55 (0.24 to 0.87)	0.00058
	Q3 vs Q1	−0.03 (−0.33 to 0.26)	0.81406	−0.03 (−0.37 to 0.3)	0.84394
	Q4 vs Q1	−0.05 (−0.38 to 0.29)	0.78771	0.07 (−0.33 to 0.47)	0.72515
	Age	0.09 (0.07 to 0.1)	< 0.001	0.09 (0.07 to 0.1)	< 0.001
	CCI	0.34 (0.29 to 0.39)	< 0.001	0.34 (0.29 to 0.39)	< 0.001
LoS 1 year	Intercept	−6.32 (−8.06 to −4.59)	< 0.001	−6.6 (−8.35 to −4.85)	< 0.001
	Q2 vs Q1	0.38 (−0.04 to 0.79)	0.07727	0.5 (0.08 to 0.91)	0.02015
	Q3 vs Q1	0.34 (−0.04 to 0.73)	0.08001	0.42 (−0.03 to 0.86)	0.06452
	Q4 vs Q1	−0.71 (−1.15 to −0.26)	0.00197	−0.4 (−0.94 to 0.13)	0.139
	Age	0.16 (0.14 to 0.18)	< 0.001	0.16 (0.14 to 0.19)	< 0.001
	CCI	0.55 (0.48 to 0.62)	< 0.001	0.56 (0.49 to 0.63)	< 0.001
LoS 3 years	Intercept	−6.81 (−8.66 to −4.96)	< 0.001	−7.1 (−8.96 to −5.23)	< 0.001
	Q2 vs Q1	0.37 (−0.08 to 0.82)	0.1045	0.37 (−0.07 to 0.82)	0.10097
	Q3 vs Q1	0.27 (−0.14 to 0.68)	0.20276	0.46 (−0.01 to 0.93)	0.0559
	Q4 vs Q1	−0.87 (−1.34 to −0.39)	0.00038	−0.63 (−1.2 to −0.06)	0.03038
	Age	0.17 (0.15 to 0.2)	< 0.001	0.18 (0.15 to 0.2)	< 0.001
	CCI	0.59 (0.51 to 0.66)	< 0.001	0.59 (0.51 to 0.66)	< 0.001

95% CI: 95% confidence interval; CCI: Charlson Comorbidity Index; LoS: length of stay; p: p-value; Q: Patients were split into four groups based on the proportion of surgery performed at the hospital they were treated, low proportion, Quartile 1, and high proportion Quartile 4.

County-level analyses similarly showed no differences in initial LoS, but cumulative LoS at 3 years was shorter for Q4 counties (Table 2). Analyses by hospital deciles showed no initial LoS differences; however, consistent with the quartile analysis, LoS was shorter at 1 and 3 years for hospitals in the highest decile of surgery (Supplementary Table 5).

Survival

Mortality was higher at Q1 hospitals compared with Q4 hospitals (Fig. 2). After adjusting for age and comorbidity, the HR for all-cause mortality was 0.92 (95% CI = 0.85–0.99) in Q3 versus Q1 and 0.92 (95% CI = 0.84–1.01) in Q4 versus Q1 (Table 3). Each additional year beyond age 70 was associated with a 10% increase in mortality (HR = 1.10, 95% CI = 1.10–1.11).

Fig. 2.

Kaplan–Meier curve showing estimated cumulative death rates among patients aged ⩾ 70 years with cholecystitis in Sweden (2015–2019), stratified by hospital surgical rate quartile (Q1: lowest, Q4: highest).

Table 3.

Cox proportional hazards analysis for mortality in patients ⩾ 70 years old with cholecystitis in Sweden 2015–2019 stratified by hospital surgical rate quartiles.

Unadjusted estimates	HR (95% CI)	p
Q2 vs Q1	0.95 (0.88–1.03)	0.24008
Q3 vs Q1	1.01 (0.94–1.09)	0.80011
Q4 vs Q1	0.91 (0.83–0.99)	0.03254
Adjusted estimates	HR (95% CI)	p
Q2 vs Q1	0.93 (0.86–1.01)	0.10032
Q3 vs Q1	0.92 (0.85–0.99)	0.0308
Q4 vs Q1	0.92 (0.84–1.01)	0.07999
Age	1.10 (1.10–1.11)	< 0.001
CCI	1.27 (1.25–1.28)	< 0.001
Subgroup age over 80	HR (95% CI)	p
Q2 vs Q1	0.97 (0.88–1.07)	0.56704
Q3 vs Q1	0.97 (0.89–1.07)	0.56518
Q4 vs Q1	0.96 (0.86–1.08)	0.50266
CCI	1.23 (1.21–1.24)	< 0.001
Gallstone-related mortality (including surgical mortality)	HR (95% CI)	p
Q2 vs Q1	0.97 (0.78–1.21)	0.77386
Q3 vs Q1	0.83 (0.67–1.02)	0.07006
Q4 vs Q1	0.90 (0.7–1.14)	0.37688
Age	1.12 (1.11–1.14)	< 0.001
CCI	1.25 (1.22–1.29)	< 0.001

95% CI: 95% confidence interval; HR: hazard ratio; Q: quartile proportion of surgical treatment; Q1 Lowest. Q4 Highest.

In patients ⩾ 80 years (n = 5312), no significant mortality differences were observed across quartiles. Comparison of the lowest and highest hospital deciles showed no significant survival difference after adjustment for age and comorbidity (HR = 0.88, 95% CI = 0.78–1.00; p = 0.059; Supplementary Table 6). No differences were observed for gallstone-related mortality or for patients aged > 80 years.

At the county level, patient treated in Q4 counties had improved survival compared with Q1 counties (HR = 0.86, 95% CI = 0.77–0.96; Supplementary Table 7). A funnel plot of hospital size and mortality is presented in Supplementary Figure 1. Kaplan–Meier curves for hospital deciles and county quartiles are shown in Supplementary Figures 2 and 3.

In a sensitivity analysis excluding the 1349 patients coded with K80.1 (chronic cholecystitis), the results were unchanged. Survival remained similar across hospital quartiles, and cumulative LoS was shorter at Q4 hospitals compared with Q1–3.

Discussion

In this nationwide cohort of patients aged over 70 years with acute cholecystitis, mortality was lower in counties with higher rates of early cholecystectomy, even after adjusting for age and comorbidities. At the hospital level, however, no differences were observed despite wider variation in surgical rates. Initial LoS did not differ between low- and high-surgery hospitals, but cumulative LoS over 1 and 3 years was consistently shorter at hospitals with higher surgical rates. A similar pattern was seen at the county level for 3‑year LoS.

Surgical rates varied markedly across hospitals. Paradoxically, hospitals treating healthier patient populations sometimes has lower surgical rates, whereas those treating older or more comorbid patients had higher rates. Although there was no consistent gradient in comorbidity burden, age distributions differed slightly between quartiles. Previous research indicates that health status is relatively uniform across Swedish regions, though age structures may vary.^13,14

Earlier studies have demonstrated that early surgery reduces both mortality and healthcare costs.^6,7,9 Our findings reinforce this evidence using comprehensive national registry data, showing substantial variation in management strategies across Sweden. The results support that early cholecystectomy is beneficial even in older and frail patients.

Strengths and weaknesses

Using the hospital‑ and county‑level proportion of early surgery reduces patient‑level confounding and mitigates selection bias inherent in retrospective studies. The true effect of early surgery is likely larger than observed, as only intermediate-risk patients, whose management varies by hospital policy, drive the estimates. Comorbidity levels were similar across hospitals, and population differences are unlikely to explain the large variation in surgical rates (17%–73%). Although care pathways may differ, this study focused on the initial management decision. Delayed surgery had minimal influence on outcomes, given its low overall use (5%).

The nationwide registries include essentially all new gallstone-related hospital contacts, with complete follow-up for mortality and readmissions through 2022. While administrative data lack detail on frailty and disease severity, the CCI method used is validated for Swedish registries.^18,20 The retrospective design remains a limitation. To avoid confounding from the COVID-19 pandemic, only patients treated before 2020 were included.

Unmeasured confounding cannot be fully excluded. A Directed Acyclic Graph (DAG) informed covariate selection, and no plausible confounders were identified that would invalidate surgical rates as an instrumental variable. Adjusted analyses accounted for differences in age and comorbidity. Factors such as patient preference, inter-hospital transfers, frailty, or variation in cholecystitis severity are unlikely to explain the broad range of surgical rates.

This study compares treatment strategies rather than individual interventions and therefore cannot determine and optimal surgical proportion. However, the findings suggest that more patients could be suitable candidates for early surgery than those who received it during 2015–2019.

Future perspective

The ⩾70-year threshold ensured adequate statistical power. Limiting analysis to patients ⩾ 80 years would have substantially reduced sample size during the study period. As operative rates increase following national guideline implementation, future studies may better evaluate outcomes in the oldest and most frail subgroups.

A randomized controlled trial is unlikely, given prior evidence supporting early surgery in healthier patients and the practical challenges of recruiting frail elderly individuals.^7–9,12,21 This study adds population-level evidence that greater use of surgical management reduces readmissions and cumulative LoS without increasing mortality. Despite high surgical rates in Q4 hospitals, recurrences remained common among patients not operated on. Further increasing the use of early cholecystectomy, through standardized care pathways, multidisciplinary decision-making, and benchmarking regional practices, may improve outcomes.

Nevertheless, an upper threshold likely exists beyond which expanding surgery confers diminishing benefit. Hospitals with high surgical rates may need to refine patient selection, while those with lower rates may consider allocating additional resources to broaden surgical access.

Conclusion

Although mortality did not differ substantially between hospitals with the highest and lowest surgical rates, recurrence rates and cumulative LoS were lower at hospitals performing more early cholecystectomies. At the county level, higher surgical proportions were associated with improved survival. These findings suggest that, even among frail and elderly patients, early surgery for cholecystitis provides meaningful benefits for both patients and the health care system.

Supplemental Material

sj-docx-1-sjs-10.1177_14574969261431971 – Supplemental material for Cholecystectomy or non-operative management for cholecystitis in elderly patients: An analysis based on hospital practice patterns

Supplemental material, sj-docx-1-sjs-10.1177_14574969261431971 for Cholecystectomy or non-operative management for cholecystitis in elderly patients: An analysis based on hospital practice patterns by Maria Söderström, Olov Norlén, Fredrik Linder and Erik Osterman in Scandinavian Journal of Surgery

Footnotes

Acknowledgements

We want to thank all hospitals reporting data to the Swedish Board of Health and Welfare.

Author contributions

Maria Söderström: Conceptualization, Writing – Review and Editing.

Olov Norlen: Conceptualization, Methodology, Writing – Review and Editing.

Fredrik Linder: Conceptualization, Methodology, Writing – Review and Editing.

Erik Osterman: Resources, Conceptualization, Methodology, Formal Analysis, Writing – Original Draft.

Clinical trials registration

Not applicable. Not a clinical trial.

Data availability

The data that support the findings of this study are available from the Swedish National Board of Welfare. Restrictions apply to the availability of these data, which were used under license for this study.

Declaration of conflicting interests

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

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Funding came from Gävleborg County Council (grant numbers CFUG-978856 and CFUG-9788509) and from the Regional Agreement on Medical Training and Clinical Research (ALF) between the Uppsala County Council and Uppsala University.

Research ethics and patient consent

The study was approved by the Swedish Ethics Review Authority dnr 2022-06449-01 and 2023-01971-01. The Swedish Ethics Review Authority waived the need for informed consent since anonymized, retrospective administrative data was used for the study.

ORCID iD

Erik Osterman

Supplemental material

Supplemental material for this article is available online.

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