Vidar Søyseth (PhD), Jurate Saltyte-Benth (PhD), Anne Siri Furuseth (MD), Faiza Mahmood (student), Knut Stavem (PhD).Akershus University Hospital, 1478 Lørenskog, Norway
Patients hospitalized for pneumonia have higher incidence of lung cancer in the next 6 years than a general population.
Background. It is well known among clinicians that patients with pneumonia have increased an increased incidence of lung cancer. The literature is, however, sparse. We compared the incidence of lung cancer among patients hospitalized for pneumonia with a comparable general population.
Methods. The patients (index group, N=7,044) were hospitalized for pneumonia in the period 01-Jan-1988 to 31-Dec-2002 at Akershus University Hospital. The reference group was recruited from a general population, the so-called HUNT study (N=81,373) during 1984-86 and 1995-97. Information on smoking habits was obtained in both groups. Information about lung cancer, death and emigration was obtained from the Cancer Registry of Norway. All individuals were followed until 31-Dec-2003. Data were analyzed using multivariate Poisson regression.
Results. The number of lung cancers was 177 and 608 in the index group and the reference group, respectively. In the multivariate analyses, incidence density ratio (IDR) and the corresponding 95% confidence interval (95% CI) was 11.2 (8.3-15.0) among the patients compared with the references. IDR during 0-3 months after inclusion was 75.5 (38.6 147.9), and showed a marked drop thereafter. However, a persisting elevated IDR was observed as long as 3-6 years after inclusion to the study estimated to 2.6 (1.6-4.3).
Conclusion. Patients hospitalized for pneumonia had an elevated incidence of lung cancer compared with a general population, which persisted for 6 years after the onset of the lung i ection.nf