Objectives: This study sought to investigate the incidence and factors associated with hospital-acquired malnutrition in children.

Design: A hospital-based longitudinal survey carried out between December 2013 and February 2014.

Setting: Aga Khan University Hospital, Nairobi, Kenya, a tertiary care hospital.

Subjects: One hundred and seventy children who met the inclusion criteria were included in the study.

Outcome measures: Anthropometry was done at admission and discharge. Incidence of hospital-acquired malnutrition was estimated from the total number of children showing a decrease in weight-for-height/length (WFH) or Body Mass Index (BMI) z-scores from the time of admission to discharge. Logistic regression analysis was performed to determine associations between selected variables and weight loss during hospitalisation.

Results: Albeit a borderline level of significance, a decrease in calculated z-scores occurred in 60.6% (Confidence Interval (CI) 53.1–67.6%) of children during hospitalisation with a mean weight decrease of 0.5 kg (Standard Deviation (SD) ± 3.37, p = 0.055). Children ≤ 60 months of age demonstrated a mean decrease in weight-for-height/length z-score of 0.145 (SD ± 0.73, p = 0.042); and those > 60 months, a mean decrease in BMI z-score of 0.152 (SD ± 0.39, p = 0.004). The majority with weight loss had been admitted with a diagnosis of gastroenteritis (81.2%), gastritis (64.3%) and pneumonia (55.6%). Weight loss was associated with duration of admission: 3 - 5 days (Odds Ratio (OR) 2.43, CI 1.46–4.03), 5 - 7 days (OR 4.67, CI 1.34–16.24), and > 7 days (OR 2.75, CI 0.88–8.64); score test for trend of odds is OR 1.37 (95% CI 1.11–1.69, p = 0.003).

Conclusion: This study found a high incidence of hospital-acquired malnutrition in children. The most affected were those with gastroenteritis, gastritis and pneumonia. Hospital-acquired malnutrition was associated with an increased duration of hospitalisation.