Glomerulonephritis (GN) is a major contributor to chronic kidney disease (CKD) in developing nations. In Bangladesh, the prevalence of CKD and end-stage renal disease (ESRD) is rising, with GN being a predominant underlying cause. [1] GN encompasses a diverse group of kidney disorders typically characterized by hematuria, proteinuria, hypertension, and varying degrees of impaired renal function. GN can be classified into primary (or idiopathic) GN, which arises intrinsically in the kidneys, with no identifiable systemic causes; and secondary GN, where glomerular injury results from systemic diseases, infections, drugs, or other extra-renal conditions. In the worldwide context, IgA nephropathy is the most common form of GN. While post-streptococcal GN has declined in developed countries, it remains prevalent in low- and middle-income regions such as Africa, South Asia, and Latin America, often contributing to acute kidney injury and requiring dialysis. [2] In many cases, patients initially present with mild or asymptomatic urinary abnormalities, occasionally accompanied by reduced glomerular filtration. Disease progression may be indolent, though relapses are not uncommon, particularly in disorders such as IgA nephropathy and C3 glomerulopathy [3] Diagnosis relies mainly on renal biopsy, which reveals inflammation and distinct histopathological patterns depending on the site and severity of injury. Management of GN involves a multifaceted approach, including supportive therapy to alleviate symptoms, renin-angiotensin-aldosterone system (RAAS) blockade to control hypertension and reduce proteinuria, and the use of immunosuppressive agents in cases involving immune-mediated pathology. In advanced stages, where significant renal impairment or failure occurs, renal replacement therapy, such as dialysis or even, kidney transplantation, may become necessary in order to sustain renal function. The outcome of patients largely depends on the specific underlying cause, ranging from complete recovery to progression towards ESRD. [4] The pattern of glomerular diseases shows significant variation across different countries, which may be attributed to differences in geography, socioeconomic status, sanitation, genetic background and ethnic diversity. [5] While chronic diseases such as diabetes and hypertension are the leading causes of CKD, glomerular disorders continue to play a crucial role, especially in low- and middle-income countries. [1, 6] Recent regional studies reveal considerable variation in GN subtypes across the nation. For instance, at Mymensingh Medical College Hospital, analyses of 101 biopsy-proven cases identified mesangial proliferative GN and focal segmental glomerulosclerosis (FSGS) as the most frequent histological forms (each 18.8%), with membranoproliferative GN (16.8%), lupus nephritis (13.9%), and minimal change disease (5.9%) also contributing notably. [7] Changing patterns due to improved diagnostic practices and shifting environmental exposures necessitate updated epidemiological data. Furthermore, understanding the clinical presentation and outcomes of GN is critical for optimizing management and preventing disease progression, especially in resource-constrained healthcare settings. A comprehensive and up-to-date investigation is therefore required to elucidate the epidemiology, clinical presentation, and outcomes of GN in Bangladesh. The aim of the study was to evaluate the epidemiological trends, clinical profiles, and outcomes of GN in a cohort of patients from a tertiary care center in Dhaka, Bangladesh.

Study Design and Setting This was a retrospective, observational study conducted in the Department of Nephrology, Bangladesh Medical College Hospital (BMCH), Dhaka, Bangladesh. The study was carried out from June 2018 to June 2025 and included patients who underwent renal biopsy based on specific clinical indications. Study Population and Sample Size A sum of 498 patients with histologically adequate native kidney biopsy samples who completed minimum 12 months of treatment were included in the study. The sampling method employed here was convenient method. As this was a single-center observational study aimed at describing the epidemiological and clinical spectrum of glomerulonephritis in a regional population, all consecutive cases who fulfilled the eligibility criteria during the specified study period were included to maximize data representativeness and minimize selection bias. No formal sample size calculation was performed, as the study was not designed to test a specific hypothesis, but to provide comprehensive regional insights All biopsy specimens were assessed using light microscopy and immunofluorescence techniques. Patient follow-up was conducted as per KDIGO 2021 guidelines [8] with regular monitoring of clinical features, blood pressure, urine R/M/E, urine for PCR, renal function tests and treatment-related adverse effects at intervals based on disease severity and response to therapy. Selection criteria Inclusion criteria • Patients presenting with nephrotic syndrome, nephritic syndrome or rapidly deteriorating kidney function (defined as rising serum urea/creatinine and/or oliguria within days to weeks). • Age ≥ 12 years. • Those patients with isolated hematuria or proteinuria. • Patients with unknown etiology of CKD. • Patients who provided written, informed consent (above 18 years) or those who provided assent and guardians provided consent (from 12-18 years) Exclusion criteria • Those patients with diabetic retinopathy with typical features of Diabetic Kidney Disease (DKD), Type 1 Diabetes duration <5 years with sudden proteinuria, active urinary sediment or hematuria, rapid unexplained renal decline or signs on non-DKD. [9] • Patients with solitary kidney or bilateral small kidneys. • Patients with active infections contraindicating biopsy. • Patients with bleeding disorders or other contraindications to percutaneous renal biopsy. • Those patients with clinical features suggestive of typical post-streptococcal GN or post-infectious GN were excluded. Data collection Demographic data, medical history and key clinical findings were documented using a structured questionnaire. Fundoscopic examination was performed in case of people with diabetes. Investigations All patients underwent the following baseline investigations: • Urine routine microscopic examination (Urine R/M/E) • Complete blood count (CBC) • Renal function tests (RFT) • HBsAg, Anti HCV • Ultrasound of KUB region • Serum complement levels (C3, C4) • 24-hour UTP • Screening for infectious foci (e.g., chest X-ray, blood/urine cultures if relevant) Renal biopsy procedure Renal biopsies were performed under ultrasound guidance using an automated biopsy gun. Biopsy samples were processed for: • Light microscopy (LM): Stains used included Hematoxylin and Eosin (H&E), Periodic Acid-Schiff (PAS), Masson’s Trichrome, and Jones Silver Methenamine. • Immunofluorescence (IF): Evaluation for IgA, IgG, IgM, C3, and C1q deposition was performed using direct immunofluorescence techniques. All biopsies were evaluated by a trained renal pathologist, and histopathological diagnoses were recorded. Biopsy results were also correlated with age, history, clinical features and biochemical parameters of the patients. Treatment details Patients were managed based on histopathological findings. Treatment was given according to updated KDIGO guidelines. [8] Outcome evaluation Patients were followed up after 12 months post-biopsy, and outcomes were categorized as follows:  Remission  Partial recovery  Relapse  Steroid-dependent  Steroid-resistant  Progression to CKD Statistical analysis All collected data were entered and analyzed using Statistical Package for Social Sciences (SPSS version 26.0). Continuous variables were expressed as mean ± standard deviation (SD) or median (interquartile range), while categorical variables were presented as frequencies and percentages.

Table 1: Socio-demographic characteristics of the participants (n=498). Variable Category Frequency/Percentage (n/%) Gender Male 290 (58.2) Female 208 (41.8) Age group and mean age (in years) 13-18 14 (2.8) 19-30 148 (29.7) 31-45 208 (41.8) >45 128 (25.7) Mean age (± SD) 33.8 (± 5.89) Area of residence Rural 320 (64.3) Urban 178 (35.7) Socio-economic status Low 417 (83.7) Middle/High 81 (16.3) Family size ≤4 members 82 (16.5) 5-6 members 351 (70.5) ≥6 members 65 (13.0) *SD: Standard deviation Table 1 highlights the socio-demographic attributes of the respondents. The mean age was 33.8 (± 5.89) years and majority [290 (58.2%)] were males. Most of the participants hailed from rural settings [320 (64.3%)] and belonged to low socio-economic status [417 (83.7%)]. In addition, majority of the families consisted of 5-6 members [351 (70.5%)]. Table 2: Clinical presentation of GN (n=498). Type of presentation Frequency/Percentage (n/%) Nephrotic syndrome 239 (47.9) Nephritic and nephrotic syndrome 87 (17.5) Nephritic syndrome 54 (10.8) RPGN 35 (7.0) Isolated proteinuria 29 (5.8) Isolated hematuria 22 (4.4) CKD of unknown cause 20 (4.0) Unexplained AKI 12 (2.4) *RPGN: Rapidly Progressive Glomerulonephritis; *CKD: Chronic Kidney Disease; *AKI: Acute kidney injury. Table 2 presents the clinical manifestations of GN in the patients. The most frequent clinical presentation was nephrotic syndrome, observed in 239 cases (47.9%). This was followed by a combination of nephritic and nephrotic syndrome, present in 87 patients (17.5%), and nephritic syndrome alone, identified in 54 patients (10.8%). A smaller subset presented with CKD of unknown cause (20 patients; 4.0%) and unexplained AKI (12 patients; 2.4%). These findings highlight the heterogeneity of GN presentations. Table 3: Histopathological patterns observed on renal biopsy (n=498) Histological pattern Frequency/Percentage (n/%) Primary 420 (84.3) Secondary 51 (10.2) TIN 20 (4.0) Chronic sclerosing GN 7 (1.4) *TIN: Tubulo-interstitial nephritis. Table 3 outlines the distribution of histopathological diagnoses based on renal biopsy findings. It is clearly evident that, the majority of cases were classified as primary glomerular diseases (420 cases; 84.3%), while secondary glomerular diseases accounted for 51 cases (10.2%). TIN was identified in 20 cases (4.0%), and chronic sclerosing GN was the least common pattern, observed in 7 cases (1.4%). Table 4: Histological subtypes of primary and secondary GN (n=471) Histological subtypes Frequency/Percentage (n/%) Primary GN Mesangioproliferative GN 129 (27.4) Diffuse MPGN 101 (21.4) FSGS 58 (11.6) IgA nephropathy 52 (11.0) MN 36 (7.6) Crescentic GN 23 (4.8) MCD 10 (2.1) C3GN 7 (1.5) C1Qgn 4 (0.8) Total 420 (89.2) Secondary GN Lupus nephritis 29 (6.2) Diabetic glomerulosclerosis 15 (3.2) Amyloidosis 7 (1.5) Total 51 (10.8) *MPGN: Membranoproliferative Glomerulonephritis; FSGS: Focal segmental glomerulosclerosis; MN: Membranous nephropathy; MCD: Minimal change disease; C3GN: C3 Glomerulonephritis; CIqGN: C1Q nephropathy. Table 4 depicts the distribution of specific histological subtypes among patients diagnosed with either primary or secondary GN. The results reflect that, Primary GN accounted for 420 cases (89.2%), with the most frequently encountered subtypes being mesangioproliferative GN (27.4%) and diffuse MPGN (21.4%). In addition, among the secondary GN cases (51 patients; 10.8%), LN was the predominant subtype (6.2%). Figure 1 shows a bar chart which demonstrates the distribution of histological categories of LN. It can be seen that; Class IV was the most commonly found category [16 (55.2%)] followed by Class III [8 (27.6%)]. Table 5: Outcomes of the most common histological subtype of primary and secondary GN (n=158). Outcomes Frequency/Percentage (n/%) Mesangioproliferative GN (n=129) Complete remission 108 (83.7) Progression to ESRD 13 (10.1) Steroid-dependent 6 (4.7) Steroid-resistant 2 (1.5) Lupus nephritis (n=29) Complete remission 18 (62.1) Progression to ESRD 6 (20.7) Relapse 5 (17.2) *ESRD: End-stage renal disease Table 5 summarizes the treatment outcomes of patients diagnosed with mesangioproliferative GN, the most common histological subtype of primary GN in along with LN, the commonest subtype of secondary GN. For mesangioproliferative GN, a high rate of complete remission was observed in 108 patients (83.7%). However, 13 patients (10.1%) progressed to end-ESRD despite therapy. On the contrary, in case of LN, complete remission was achieved in 18 patients (62.1%), while 6 patients (20.7%) progressed to ESRD.

The present study offers valuable insights into the demographic, clinical and histological characteristics of GN in Bangladesh, encompassing both primary and secondary forms as well as associated treatment outcomes. The study discovered that, the mean age was 33.8 ± 5.9 years, with marginal male predominance (58.2%), hailing from rural settings to the greater extent (64.3%), low socio-economic status (83.7%), and large family units (70.5%). These socio-demographic characteristics reflect the continued obstacles in Bangladesh’s health infrastructure, where rural and low-income populations are inflicted with the challenges of delayed diagnosis and diminished accessibility to health-care services. Our findings align with previous studies. For instance, Ahmed et al. reported a mean age of 32.94 ± 12.66 years among GN patients at Dhaka Medical College Hospital, with a male-to-female ratio of 1.8:1. [10] Furthermore, a study in a sub-urban region of Bangladesh reported that, the predominant socioeconomic class of study population was lower middle class which belonged to 45% of the participants, followed by lower class (35%). [6] In addition, nephrotic syndrome remained the most common clinical presentation (47.9%), followed by mixed nephritic–nephrotic presentation (17.5%) and pure nephritic syndrome (10.8%). Previous study conducted in northern part of Bangladesh expressed similar findings where the most frequent clinical presentation was nephrotic syndrome (67.37%). [11] These findings stress that, there is a predominance of heavy proteinuria-based manifestations in glomerular disease; highlighting the dire needs for early proteinuria screening in vulnerable populations. On the contrary, data from Western registries indicate a distinct diagnostic trend. It has been found that, renal biopsies are more frequently performed for subnephrotic proteinuria, isolated microscopic hematuria, or nephritic presentations such as incidentally detected IgA nephropathy—implying earlier disease recognition and varying epidemiological patterns. [12] Primary glomerular diseases constituted the vast majority (84.3%), with mesangioproliferative GN (27.4%) and diffuse MPGN (21.4%) being the most frequent subtypes. Besides, LN represented the leading cause of secondary GN (6.2%), followed by diabetic glomerulosclerosis (3.2%) The predominance of LN over diabetic glomerulosclerosis in our biopsy-based investigation likely reflects both clinical and procedural factors. LN, being systemic with high therapeutic stakes, compels clinicians to seek histological confirmation for classification and treatment decisions. In contrast, diabetic nephropathy, typically with gradual onset and well characterized clinical progression, is mostly managed without biopsy unless atypical features emerge (e.g., absence of retinopathy, hematuria, or rapid disease progression). [13] Moreover, as a specialized referral center, our institution predominantly receives complex systemic cases such as LN, leading to their overrepresentation in the biopsy spectrum. In contrast, typical cases of diabetic nephropathy—especially those not fulfilling biopsy criteria—are often managed conservatively at primary or secondary care levels and thus remain underrepresented. [14] In alignment with our findings, previous study from Khulna, Bangladesh displayed a predominance of primary GN, accounting for approximately 91% of cases, while secondary glomerulonephritis represented only 9%. Among primary GN, mesangioproliferative glomerulonephritis was the most frequently encountered histological pattern, though recent data suggest a gradual decline in its prevalence (36.5%). Membranoproliferative GN follows as the second most common subtype (27%). Furthermore, consistent with regional patterns, LN was found to be the leading cause of secondary GN. [14] On the contrary, results from non-Asian populations indicate different trends. Glomerular diseases constituted the predominant pathological diagnosis, accounting for 44.9% of cases. Among these, amyloidosis and focal segmental glomerulosclerosis (FSGS) emerged as the most frequently observed glomerular pathologies, representing 15.2% and 14.3% of cases, respectively. [15] Furthermore, studies from western communities reveal a different histological pattern. For instance, in a large biopsy-based registry from the United States, FSGS was the most prevalent primary GN, particularly among African-American populations, reflecting the impact of APOL1 gene polymorphisms. [16] These regional differences highlight how an amalgamation of genetic predisposition, screening policies, and healthcare access give outlook to the epidemiology of GN. We found Class IV LN to be most commonly encountered. Similarly, in a study conducted in Rangpur, Bangladesh, Class IV LN was the predominant subtype, accounting for 46.7% of cases, followed by Class III (26.7%) and Class V (20%). [17] The findings reflect the aggressive nature of proliferative LN in the local population and the urgency for optimum immunosuppressive therapy. When the extra-renal features of LN were taken into concern, out of 29 patients, 22 developed those; among them, majority were found to be affected with arthritis, oral ulcers, malar rash and hematological abnormalities. Previous study in Bangladesh generated similar findings in which, arthralgia (82.4%), malar rash (73.5 %) and oral ulcers (38.2%) were the most common extra-renal features of LN. [18] In our study, outcomes of mesangioproliferative GN were favorable overall: complete remission in 83.7%, ESRD progression in 10.1%, with steroid dependence and resistance in 4.7% and 1.5%, respectively. However, another study in Egypt suggested poor outcomes—including the need for renal replacement therapy or mortality—were observed in 43.6% of the cohort, highlighting the significant morbidity associated with these conditions. Their results emphasize the significance of early immunosuppression and continuous follow-up. [15] From a Western context, mesangioproliferative GN tends to exhibit a relatively favorable trajectory. For example, a Danish cohort revealed a 30 year renal survival ranging from 50% to 87%, with markedly better outcomes in women. [19] Among LN patients, 62.1% achieved complete remission, 20.7% progressed to ESRD, and 17.2% experienced relapse. It is worth mentioning that, despite advances in therapy, LN remains a formidable cause of renal morbidity. Outcomes of LN in neighboring Eastern India revealed that, roughly two-thirds of proliferative LN cases respond to treatment within a year, but poorer outcomes cluster among patients with higher disease activity, hypertension, and delayed or inadequate histopathological-guided therapy. [20] Furthermore, A population based study documented that over 14% of LN patients progressed to ESRD, with stable CKD/ESRD rates over time. [21] Moreover, even though survival has improved drastically, for instance, 5 year mortality in one UK cohort dropped by 60%; the risk of ESRD (7–8% at 5 years) has remained stagnant, glorifying the need for more effective renal protective strategies. [22] While this study sheds light on the burden and characteristics of GN in Bangladesh, it is not without flaws. Limitations include its limited long-term follow-up beyond initial remission or progression to ESRD, and the lack of detailed data on specific treatment regimens that may impact patient outcomes. Establishing national biopsy registries and conducting prospective, multi-center studies would significantly enhance the epidemiological knowledge and prognostic evaluation of GN in this region.

The predominance of mesangioproliferative GN, together with high remission rates along with significant risk of progression to ESRD, highlights the critical need for ongoing long-term follow-ups and strengthening nephrology services in rural and underprivileged settings. In the case of LN, the considerable risks of relapse and disease progression stress the significance of early detection, accurate histopathological diagnosis, and tailored immunosuppressive treatment strategies that consider local healthcare boundaries. Targeting these hurdles require holistic policy interventions to improve equity in the diagnosis and management of GN across vulnerable regions of Bangladesh.

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