Hospital inpatient admissions of children of mothers with severe mental illness: A Western Australian cohort study

Background: Children of parents with mental illness face a number of adversities, potentially contributing to poor health. Aim: The aim of this study was to quantify the association between maternal severe mental illness and children's hospital admissions. Method: Record linkage cohort study of 467,945 children born in Western Australia between 1 January 1980 and 31 December 2001. Follow-up was from age 28 days until fifth birthday. Linked registers captured information on potential confounders. Rate ratios and adjusted rate ratios measured relative change in the numbers of admissions and total days of stay, while rate differences measured absolute change in outcomes. Cause-specific increases were calculated for ICD-9 chapters and for 'potentially preventable' conditions. Results: After adjusting for potential confounders, children of mothers with severe mental illness had a 46% relative increased rate in hospital admissions (95% confidence interval = [38%, 54%]) and an absolute increase in 0.69 extra days in hospital per child, per year (95% confidence interval = [0.67, 0.70]). The relative increase in admissions was greatest in the child's first year of life (adjusted rate ratio = 1.76, 95% confidence interval = [1.64, 1.88]; rate difference = 0.32, 95% confidence interval = [0.30, 0.34]). Rates of admissions were increased for a range of causes, particularly injuries, infections and respiratory disease, and for conditions classified as 'potentially preventable'. Conclusion: Children of mothers with severe mental illness have a substantial excess in hospital use compared to children of well mothers. This vulnerable group should be targeted with interventions to avert preventable morbidity and premature mortality in later life.