A STUDY OF HOSPITAL ADMISSIONS OVER TIME, USING LONGITUDINAL LATENT STRUCTURE-ANALYSIS

The aim was to study patterns of utilization of non-psychiatric admiss ions over time and factors affecting the utilization. The study cohort includes all individuals born 1934-66, living in one of two Danish mu nicipalities and admitted to a non-psychiatric department at least onc e in 1977 (n = 2 686). The hospitalizations of the cohort were followe d during a 5-year period by means of the Danish National Patient Regis ter. The data were analysed using a longitudinal latent class (LC) mod el and a longitudinal latent Markov (LM) model. The LC model suggests that among the cases in the cohort there were 4 variants of utilizatio n patterns. The LM model adequately described the sample in only 3 var iants or classes. These classes may be interpreted as a small group of ''chronically ill'' individuals (1.9% of the cohort), a major group o f ''healthy'' individuals, with no, or only a single, random re-admiss ion during the follow-up period (74.4% of the sample), and finally an intermediate group of ''high utilizers'' (23.7% of the sample). This ' 'chronicity'' variable was markedly associated with mental illness, mu ltiple discharge diagnoses from non-psychiatric departments and total utilization of hospitalizations during the follow-up period. Conversel y, gender, age and days in hospital per admission were without importa nce. The study implies that the analysis of patterns of hospital admis sions over time can yield important insight into health service utiliz ation and that longitudinal latent structure analyses are powerful sta tistical tools in this aspect. The data strongly indicated that a high utilization of admissions for physical illnesses (i.e. chronicity) do es not simply depend on the severity of a physical disorder, but menta l disturbances may be a more important factor.