Risk of pneumonia recurrence in patients previously hospitalized for pneumonia--a retrospective study (1998-2000).

Although elderly hospitalized patients, irrespective of the cause of hospitalization, are known to be at a high risk of subsequent development of pneumonia, some studies suggest the risk to be even higher in those hospitalized for pneumonia than in those hospitalized for other diseases. The aim of this retrospective study was to determine the association of hospitalization for pneumonia and some other diseases with subsequent pneumonia morbidity and mortality. The risk of recurrent pneumonia in patients hospitalized for pneumonia was investigated. Rehospitalization of pneumonia patients previously hospitalized for the same disease was followed-up and compared with rehospitalization of patients hospitalized for other diseases during the same study period. The study included patients aged overl8, initially hospitalized in 1998 for pneumonia (J12-J18), or for some particular gastrointestinal (K20-K31) and urogenital diseases (N10-N12, N30-N39). All rehospitalizations for pneumonia in nine Zagreb hospitals were followed-up during a 3-year study period (1998-2000). Out of 975 patients followed-up for rehospitalization, 227 (23.3%) had initially been hospitalized for pneumonia, and 748 (76.7%) for other diagnoses. During the 3-year period, 30 patients were rehospitalized for pneumonia, out of which number 22 had initially been hospitalized for pneumonia, yielding a statistically significant difference between the two study groups (chi2 = 34.780, p < 0.001). The mortality directly caused by pneumonia was also significantly higher in the group of patients with the initial diagnosis of pneumonia than in the group of patients with other diagnoses (chi2 = 15.82, p < 0.001).