Rising incidence of Kawasaki disease in Chile: analysis of national discharge databases between 2001 and 2007

Results Seven hundred eighty-six hospitalizations attributable to KD were identified between 2001 and 2007, representing 0.03% of hospitalizations in children younger than 18 years. Median age of diagnosis was 1 year (range 0-17). Twenty-five percent of patients were younger than 1 year, 60% were between 1 and 4 years, 11% between 5 and 9 years, and 4% between 10 and 17 years. Male to female ratio was 1.6:1. Median length of hospital stay was 5 days (range 1-152). Highest hospitalization rates occurred in late winter and spring (August-November) with a smaller peak in summer (February-March). Sixty percent of patients had public health insurance and 30% of patients had private health insurance, which was overrepresented among KD patients. Fifty-two percent of cases were hospitalized in the Metropolitan Region (Santiago), which had the highest KD hospitalization rate in the country. Hospitalization rate attributable to KD among children younger than 5 years was 7.6 (95% CI 7.1-7.9). Hospitalization rates significantly increased from the 2001-2004 period to the 2005-2007 period: 6.3 (95% CI 5.9-6.6) to 9.3 (95% CI 8.4-10.4), (P < 0.001). Estimated incidence of KD, assuming 10% readmission rates, was 5.7 (95% CI 5.4-6.1) per 100,000 children younger than five years for the 2001-2004 period and 8.4 (95% CI 7.6-9.6) for the 2005-2007 period (P < 0.001). Two patients died during a hospitalization attributable to KD, resulting in an acute lethality rate of 0.25%.