Hospitalizations for ambulatory care-sensitive (ACS) conditions have been considered a marker for access to timely and effective primary care, but there are few pediatric studies.  The purpose of this study was to examine socioeconomic disparities in ACS and non-ACS admissions among birth cohorts in a universal health insurance setting.

Investigators examined ACS and all hospitalizations of children born from 1993 to 2000 in Toronto, Canada, by birth year, calendar year, and socioeconomic status (SES).  SES was evaluated by using quintiles of mean neighborhood income from the 1996 Canadian census.  Cohort, age, and temporal effects were described for all admissions, ACS admissions, and specific ACS conditions.  Attributable risk by SES was calculated by using rates for the highest and lowest SES quintiles.

Among 255,284 children born in Toronto during 1993-2001, ACS conditions were responsible for 28% of hospitalizations during the first two years of life and close to half of admissions during the third year.  Low income was associated with 50% higher rates of ACS hospitalizations (relative risk [RR] = 1.50, 95% confidence interval [95% CI] 1.43-1.58), including asthma (RR = 1.69, 95% CI 1.54-1.86) and bacterial pneumonia (RR = 1.59, 95% CI 1.40-1.81), the leading causes of admission.  Socioeconomic disparities in ACS and all admissions occurred in every cohort, every calendar year, and every age group.

The relationship between socioeconomic disadvantage and both ACS and all-cause hospitalization in children was large, consistent across many conditions, remained stable over time, and persisted up to nine years of age.  These effects occurred in a universal health insurance setting without direct financial barriers to physician or hospital care.  The effect of SES on hospitalizations in children in this setting appears to be mediated by factors other than financial access to care.