Background: Children with nephrotic syndrome (NS) face increased infection risk due to immune dysregulation and immunosuppressive therapy. Pneumonia is a major cause of morbidity, but region-specific data from Iran are limited. This study aimed to determine the prevalence of pneumonia and its associated factors among hospitalized children with NS in Urmia, Iran.
Methods: A retrospective record-based study was conducted at educational therapeutic hospitals in Urmia, including children aged 4–11 years with confirmed NS hospitalized between January 1, 2020, and December 31, 2024. Pneumonia was defined using standardized World Health Organization (WHO) chest radiograph criteria, including the presence of new infiltrates, consolidation, or pleural effusion, accompanied by clinical features such as fever (≥38.0°C), tachypnea, cough, and/or oxygen desaturation. Multivariable logistic regression was used to identify factors independently associated with pneumonia.
Results: Among 206 children included in the study (median age 7.2 years; 57.3% male), the overall prevalence of radiologically confirmed pneumonia was 20.4% (95% CI: 15.1–26.6%). Community-acquired pneumonia accounted for 73.8% of cases, while nosocomial pneumonia accounted for 26.2%. The prevalence was significantly higher in children aged 4–7 years compared to those aged 8–11 years (26.8% vs. 12.8%, p=0.012) and in steroid-resistant versus steroid-sensitive NS (34.0% vs. 16.0%, p = 0.006). In multivariable analysis, after adjusting for age, sex, relapse frequency, immunosuppressive therapy, vaccination status, length of hospital stay, history of previous lower respiratory tract infection (LRTI), and seasonality, younger age (aOR per 1-year increase: 0.76; 95% CI: 0.63–0.93; p=0.006) and higher relapse frequency (aOR per additional relapse: 1.42; 95% CI: 1.12–1.81; p=0.004) remained independently associated with pneumonia. Documented pneumococcal and influenza vaccination rates were low (29.6% and 23.3%, respectively) and likely represent minimum estimates due to incomplete record-keeping.
Conclusions: Pneumonia affects one in five hospitalized children with NS in Urmia. Younger age and frequent relapses are independently associated with pneumonia in this population. Suboptimal documented vaccination coverage represents a potentially modifiable target for prevention; however, improved record-keeping is necessary to confirm true coverage rates. Clinicians should maintain a low threshold for diagnosing pneumonia and prioritize vaccination review at every healthcare encounter.