Morbidity patterns in hospitalized urology patients in Vietnam: challenges for kidney care in a low- and middle-income setting

¹Military Hospital 103, Vietnam Military Medical University, Hanoi, Vietnam

^&Corresponding author
Luong Cong Thuc, Military Hospital 103, Vietnam Military Medical University, Hanoi, Vietnam

Introduction    

Urologic diseases constitute a major source of morbidity among hospitalized patients worldwide and place substantial demands on kidney care services. Common conditions such as benign prostatic hyperplasia, urinary tract infections, urolithiasis, and urologic malignancies frequently require inpatient management and are closely associated with prolonged hospital stay and repeated admissions [1,2]. These burdens are particularly pronounced among older patients with multimorbidity and frailty, in whom renal complications and complex care needs are common. In low and middle-income settings, where health systems face limited resources and rapidly increasing demand, understanding inpatient morbidity patterns in urology is essential for improving hospital efficiency and kidney care outcomes [3,4].

At the global level, six major urologic conditions, including benign prostatic hyperplasia, urinary tract infections, urolithiasis, and cancers of the kidney, bladder, and prostate, account for a large proportion of urologic incidence, prevalence, and disability adjusted life years, with marked geographic variation [1,2,5]. Benign prostatic hyperplasia and urinary tract infections show the highest global incidence and prevalence, particularly in middle and low-middle sociodemographic index countries, whereas urologic cancers contribute disproportionately to mortality and long-term disability in higher sociodemographic index settings [1,2,5]. These patterns are amplified by population ageing and the rapid rise of multimorbidity, which affects approximately 37% of adults globally and more than 50% of individuals aged 60 years or older, leading to increased hospitalization and kidney-related service utilization across regions [6].

Evidence from high-income countries demonstrates that morbidity patterns among hospitalized urology patients are strongly linked to repeated admissions and prolonged length of stay. In a large Australian cohort of 98,72 urology inpatients, five distinct hospitalization trajectory clusters were identified, with higher trajectory groups experiencing longer length of stay, higher readmission rates, and greater complication burden [7]. Multimorbidity, including renal disease, diabetes, cardiovascular disease, liver disease, and the presence of two or more comorbidities, was a key predictor of high utilization, along with diagnoses such as urologic cancers, bladder calculi, urethral stricture, bladder neck obstruction, and benign prostatic hyperplasia [7]. More broadly, among older adults, multimorbidity has been shown to approximately double the odds of hospitalization and substantially increase readmission risk across countries at different income levels [6,8]. Frailty in major urologic oncology surgery and kidney-related admissions, such as haematuria is also independently associated with prolonged length of stay, increased short-term mortality, and high inpatient resource use [9,10].

In Vietnam, a low and middle-income country undergoing rapid demographic ageing and epidemiological transition, urology departments are increasingly confronted with complex inpatient morbidity patterns that pose significant challenges for kidney care delivery. However, comprehensive evidence describing the distribution of urologic diseases, patterns of repeated hospitalization, and prolonged length of stay among hospitalized urology patients remains limited. Generating such evidence is critical to inform clinical planning, optimize inpatient kidney care, and support health system strengthening. Therefore, the objective of this study was to characterize morbidity patterns among hospitalized urology patients in Vietnam and to identify factors associated with multiple hospital admissions and prolonged length of stay.

Methods     

Study design: this retrospective observational study analyzed routinely collected inpatient data from a tertiary urology department to characterize morbidity patterns and hospitalization dynamics among urology patients in Vietnam.

Setting: the study was conducted at the Department of Urology, Military Hospital 103, a tertiary referral hospital affiliated with Vietnam Military Medical University in Hanoi, Vietnam. The study period covered all hospital admissions between January 2021 and December 2025. Data extraction and consolidation were performed in January 2026 using the hospital electronic medical record system.

Participants: the study included all patients admitted to the Department of Urology during the study period. All inpatient records were screened for eligibility. Records with missing key variables were excluded during data cleaning. A total of 10,337 hospitalization episodes were included in the final analysis. When a patient had multiple admissions during the study period, each hospitalization episode was treated as an independent analytical unit.

Variables: the primary outcomes were (1) multiple hospital admissions and (2) prolonged length of stay (LOS). Multiple admissions were defined as more than one hospitalization episode for the same patient during the study period. Prolonged LOS was defined as a hospital stay of ≥6 days based on the LOS distribution in the study population [11-13]. Independent variables included sex, age group, primary diagnosis, disease group, patient category, mode of admission, referral status, and number of comorbidities. Treatment outcome at discharge was also described.

Data sources and measurement: clinical and administrative data were retrospectively extracted from electronic medical records using a standardized data extraction form. Sociodemographic variables included age at admission and sex. Health system variables comprised patient category (health insurance vs self-pay/on-demand) and referral status (in-network vs out-of-network). Clinical variables included the primary diagnosis coded according to the International Classification of Diseases, 10^th Revision (ICD-10), which was subsequently classified into major disease groups and the ten most frequent diagnoses. Additional extracted variables included the number of comorbidities, mode of admission, length of hospital stay, hospitalization frequency during the study period, and treatment outcomes at discharge. Age was categorized into predefined groups for analysis.

Bias: to minimize selection bias, all eligible inpatient records during the study period were included. Standardized electronic extraction procedures and predefined variable definitions were applied to reduce information bias. Records with missing key variables were excluded during data cleaning. As the study relied on routinely collected administrative and clinical data, residual misclassification related to diagnostic coding or comorbidity recording may remain.

Study size: the study included the entire population of eligible urology inpatient admissions during the five-year study period. After data cleaning, 10,337 hospitalization episodes constituted the final analytical sample. No formal sample size calculation was performed because the study used complete census data from the hospital database.

Quantitative variables: continuous variables, including age and length of stay, were summarized using means and standard deviations. Age was categorized into predefined groups for regression analysis. The number of comorbidities was treated as a count variable. Length of stay was dichotomized (<6 days vs ≥6 days) to define prolonged hospitalization. Hospitalization frequency was dichotomized (single vs multiple admissions).

Statistical methods: descriptive statistics were used to summarize patient characteristics and hospitalization patterns. Categorical variables were presented as frequencies and percentages, and continuous variables as means with standard deviations. Group comparisons were conducted using the chi-square test for categorical variables. Multivariable logistic regression analyses were performed to identify factors independently associated with multiple hospital admissions and prolonged LOS. Covariates included sex, age group, primary diagnosis (top 10 ICD-10 categories), disease group, patient category, mode of admission, referral status, and number of comorbidities. Adjusted odds ratios with 95% confidence intervals were reported. Statistical significance was defined as a two-sided p-value <0.05. All analyses were conducted using Stata statistical software.

Ethical consideration statement: the study protocol was reviewed and approved by the Ethics Committee of Military Hospital 103 (Approval Code 288B; 15 September 2025). Because the study used retrospective anonymized secondary data, the requirement for informed consent was waived. All procedures were conducted in accordance with the Declaration of Helsinki and applicable national regulations governing biomedical research involving human subjects.

Results     

Socio-demographic analysis: among 10,337 patients, older adults (≥60 years) accounted for the largest proportion (46.3%), followed by those aged 45-59 years (26.2%) and 25-44 years (23.4%). Males predominated (74.0%). Most patients were insured (89.6%) and admitted directly to hospital (58.5%) or via the emergency department (29.6%). Single admissions were more common than multiple admissions (71.4% vs 28.6%). Clinical outcomes were favorable, with 99.1% classified as improved. Prolonged hospitalization (≥6 days) occurred in 79.3% of cases. The mean age was 56.1 years, mean length of stay was 8.5 days, and the mean number of comorbidities was 1.1. (Table 1).

Descriptive analysis: overall, urolithiasis was the most common disease group (48.0%), followed by urinary tract infections (25.9%) and prostate diseases (12.3%). The most frequent primary diagnoses were other disorders of the urinary system (ICD-10 N39; 21.8%), calculus of the kidney (19.9%), and calculus of the ureter (14.0%). Benign prostatic hyperplasia accounted for 12.3% of admissions, whereas each of the remaining top diagnoses contributed 3.2% or less, with other diagnoses collectively representing 11.0% of cases (Table 2).

Bivariate analysis: there were significant differences in hospitalization frequency across both primary diagnoses and disease groups (p<0.001). Multiple admissions were more frequent among patients with other disorders of the urinary system (32.2%) and calculus of the kidney (23.8%), whereas benign prostatic hyperplasia (7.0%), bladder stones (0.9%), and donor-related diagnoses (0.0%) were predominantly associated with single admissions. At the disease-group level, urolithiasis accounted for the largest proportions in both single (47.3%) and multiple admissions (49.7%), while urinary tract infections were markedly more common among patients with multiple admissions (36.9%) than single admissions (21.4%). Prostate diseases and male genital diseases were mainly observed in single-admission cases (Table 3).

Treatment outcomes and length of stay differed significantly by both primary diagnosis and disease group. Across all categories, the vast majority of patients showed improvement (>96%), with no-change and recovery outcomes each accounting for ≤2% (p<0.001). Prolonged length of stay (≥6 days) was common, particularly in patients with kidney stones (91.7%), benign prostatic hyperplasia (91.2%), congenital urinary anomalies (94.4%), and donor-related diagnoses (≥99%) (p≤0.006). Shorter hospital stays (<6 days) were more frequently observed in unspecified renal colic (50.0%) and urinary tract infections (37.0%), while most other diagnoses and disease groups were predominantly associated with prolonged hospitalization (Table 4).

Multivariate analysis: Table 5 presents the results of multivariable logistic regression identifying factors independently associated with multiple hospital admissions and prolonged length of stay (LOS). Male sex was significantly associated with a higher likelihood of multiple admissions (OR = 1.65, 95% CI 1.47-1.85), while no significant association was observed with prolonged LOS. Compared with children, adolescents and young adults had significantly lower odds of multiple admissions but markedly higher odds of prolonged LOS, whereas middle-aged adults showed a significant increase only for prolonged LOS. Older adults were significantly more likely to experience prolonged LOS (OR = 3.32, 95% CI 1.92-5.75).

Several primary diagnoses were significantly associated with outcomes. Benign prostatic hyperplasia, cystitis, unspecified renal colic, and bladder calculus were associated with lower odds of multiple admissions, while benign prostatic hyperplasia, calculus of the kidney, and cystitis were associated with increased odds of prolonged LOS. Unspecified renal colic was associated with reduced odds of prolonged LOS, whereas organ or tissue donors had markedly increased odds of prolonged LOS. At the disease-group level, male genital diseases and other diseases were associated with fewer multiple admissions, while urinary tract infection was associated with a lower likelihood of prolonged LOS and congenital anomalies with a substantially higher likelihood.

Self-pay or on-demand patients had a markedly higher likelihood of multiple admissions compared with insured patients. Direct hospital admission was significantly associated with increased odds of multiple admissions but reduced odds of prolonged LOS, whereas emergency admission and other admission modes were associated with significantly lower odds of prolonged LOS. Out-of-network referral was significantly associated with multiple admissions. Finally, each additional comorbidity significantly increased the odds of prolonged LOS, while its association with multiple admissions was not statistically significant.

Discussion     

This large retrospective study provides a comprehensive overview of morbidity patterns among hospitalized urology patients in Vietnam and identifies key factors associated with multiple hospital admissions and prolonged length of stay. The findings highlight a patient population dominated by older males with a high burden of stone disease and urinary tract infections, substantial rates of repeated hospitalization, and a strikingly high proportion of prolonged hospital stays. Multivariable analysis demonstrated that demographic characteristics, disease profiles, admission pathways, insurance status, and comorbidity burden independently shaped hospitalization dynamics, underscoring the complexity of inpatient urologic and kidney care in a low- and middle-income setting.

The morbidity pattern observed among hospitalized urology patients in this Vietnamese cohort was dominated by benign conditions, with urolithiasis accounting for nearly half of all admissions (48.0%), followed by urinary tract infections (25.9%) and prostate diseases (12.3%). At the diagnosis level, other disorders of the urinary system (ICD-10 N39) represented the largest single category (21.8%), while calculus of the kidney (19.9%) and calculus of the ureter (14.0%) together underscored the central role of stone disease in inpatient urologic care. Benign prostatic hyperplasia alone contributed 12.3% of hospitalizations, whereas malignant and congenital conditions collectively accounted for less than 2% of admissions. This distribution aligns with global epidemiological evidence showing that benign urologic diseases such as benign prostatic hyperplasia, urinary tract infections, and urolithiasis carry the highest age-standardized incidence rates worldwide, particularly in low- and middle-income regions where access to preventive and outpatient management remains limited [1,5,14].

Notably, the disease mix in this Vietnamese inpatient cohort differs substantially from patterns reported in high-income settings. In a large Australian statewide cohort of 98,782 urology patients, prostate cancer and other urologic malignancies constituted a much larger share of hospitalizations, with prostate cancer alone ranging from 12.6% to 34.1% across hospitalization trajectory classes, while kidney stone disease accounted for only 2.8-9.6% of admissions [7]. In contrast, cancers represented just 1.0% of admissions in the present study, whereas stone disease alone contributed nearly half of all cases. This contrast reflects broader global gradients in urologic disease burden, where benign conditions dominate incidence and service utilization, while cancers contribute disproportionately to mortality and disability in higher-income health systems [1]. The predominance of stone disease and infection-related diagnoses in this cohort highlights a morbidity pattern characteristic of resource-constrained settings, emphasizing the persistent inpatient burden imposed by recurrent and potentially preventable benign urologic conditions.

Male sex was independently associated with a substantially higher likelihood of multiple hospital admissions, with a 65% increase in odds compared with female patients (OR = 1.65, 95% CI 1.47-1.85). This finding aligns closely with evidence from a large Australian urology cohort of 98,782 patients, in which men were overrepresented in higher hospitalization trajectory classes and exhibited a heavier burden of chronic comorbidities, including diabetes, cardiovascular, renal, and liver diseases [7]. Age showed a contrasting pattern across outcomes: adolescents and young adults had significantly lower odds of multiple admissions (OR = 0.24 and 0.74, respectively) but markedly higher odds of prolonged LOS, while middle-aged and older adults demonstrated progressively increased odds of prolonged hospitalization, reaching more than threefold higher odds among patients aged ≥60 years (OR = 3.32, 95% CI 1.92-5.75). This divergence suggests that repeated admissions and extended inpatient stays reflect distinct utilization pathways influenced by age-related disease complexity and functional reserve, consistent with broader multimorbidity and frailty literature [15,16].

Diagnosis-specific associations further highlight heterogeneity in utilization patterns. Several benign conditions, including benign prostatic hyperplasia, cystitis, bladder calculi, and unspecified renal colic, were associated with significantly lower odds of multiple admissions, likely reflecting effective resolution within single treatment episodes. However, these same conditions, particularly benign prostatic hyperplasia (OR = 2.12) and cystitis (OR = 1.85), were associated with significantly increased odds of prolonged LOS, indicating higher inpatient resource use per admission. Kidney stones were also strongly associated with prolonged hospitalization (OR = 2.55), consistent with prior trajectory analyses showing that stone disease contributes to longer stays when complicated by obstruction, infection, or surgical intervention [7]. Notably, congenital urinary anomalies and donor-related diagnoses were among the strongest predictors of prolonged LOS, with odds ratios exceeding fourfold and tenfold, respectively, reflecting the inherent procedural complexity and perioperative monitoring requirements of these patient groups.

Health system and patient-level factors played a critical role in shaping utilization. Self-pay or on-demand patients exhibited an exceptionally high likelihood of multiple admissions (OR = 49.42, 95% CI 18.29-133.53), suggesting delayed care seeking, fragmented outpatient follow-up, or financial barriers to definitive treatment, patterns commonly reported in lower-resource settings [17]. Out-of-network referral was also independently associated with repeated admissions (OR = 1.97), reinforcing the impact of care fragmentation. In contrast, emergency admission and other non-routine admission modes were associated with significantly lower odds of prolonged LOS, possibly reflecting streamlined acute care pathways or early discharge pressures. Finally, each additional comorbidity increased the odds of prolonged hospitalization by 22% (OR = 1.22), corroborating extensive evidence that multimorbidity and frailty, rather than single diagnoses alone, are dominant drivers of extended LOS across urology and other inpatient populations [18-20].

These findings have important implications for urology and kidney care in Vietnam and similar low- and middle-income settings. The dominance of stone disease and infections highlights the need for stronger prevention strategies, including metabolic evaluation, infection control, and improved outpatient management to reduce avoidable hospitalizations. High rates of prolonged length of stay suggest opportunities for care pathway optimization, early risk stratification, and multidisciplinary management of older and multimorbid patients. Addressing disparities related to insurance coverage and referral systems is also critical to reducing repeated admissions and improving continuity of kidney care.

The major strength of this study lies in its large sample size and comprehensive inclusion of all hospitalized urology patients over multiple years, enabling robust assessment of morbidity patterns and associated factors. The use of multivariable modeling allowed adjustment for key confounders and provided insight into independent associations. However, several limitations should be acknowledged. The retrospective design limits causal inference, and the analysis was based on administrative and clinical records without detailed information on disease severity, frailty indices, or outpatient care. Additionally, the study was conducted at a single tertiary hospital, which may limit generalizability to other settings, particularly primary or provincial hospitals.

Conclusion     

In conclusion, hospitalized urology patients in Vietnam exhibit a morbidity pattern dominated by urolithiasis and urinary tract infections, accompanied by high rates of prolonged hospitalization and substantial repeated admissions. Ageing, disease type, admission pathways, insurance status, and comorbidity burden independently shape these outcomes. These findings underscore the need for targeted strategies to strengthen kidney and urologic care across the continuum, with a focus on prevention, continuity of care, and efficient inpatient management in low- and middle-income health systems.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

Le Dinh Nguyen: study design, data collection, data analysis, and manuscript drafting. Duong Minh Hieu: data acquisition, clinical data validation, and manuscript revision. Dinh Van Thinh: data management, statistical support, and results interpretation. Do Anh Quan: clinical interpretation, urologic expertise input, and manuscript editing. Nguyen Phu Viet: literature review, data verification, and manuscript revision. Luong Cong Thuc: conceptualization, methodological supervision, interpretation of findings, critical revision, and overall supervision of the study. All authors read and approved the final manuscript.

Tables     

Table 1: baseline characteristics of the study population (N = 10,337)

Table 2: distribution of disease groups and top primary diagnoses (N = 10,337)

Table 3: single versus multiple hospital admissions by disease groups and primary diagnoses (N = 10,337)

Table 4: treatment outcomes by disease group

Table 5: factors associated with multiple admissions and prolonged length of stay (multivariable logistic regression)

References