The use of hospital admission data as a measure of outcome in clinical studies of heart failure

Aim To describe and evaluate the methods currently used to summarize, depict, and analyse hospitalization data in clinical studies of patients with heart failure. Methods and Results Studies published during 1999 and 2000 were reviewed if they reported hospitalization data collected during the follow-up of a defined group of adults who had been diagnosed as having heart failure. Of 130 studies identified, the majority considered only the first of any hospital admissions for each individual. When presented, statistical analyses in 70% of papers, and graphics in 75% of papers, were based purely on the first hospitalization. A minority of papers based analyses on the number of admissions (23%), or the amount of time spent in hospital by patients (14%) during the follow-up period. Conclusions Data on the hospitalizations undergone by patients with heart failure are potentially informative about the disease burden to individuals and health services. The widespread practice of focussing a statistical analysis on the first admission a patient undergoes discards those aspects of hospitalization that are informative about disease burden: multiple admissions and length of stay. Statistical methods that incorporate these aspects appeared in a handful of papers, and the more widespread adoption of these is desirable.