A COMPARISON OF POLYDIPSIA PREVALENCE AMONG CHRONIC PSYCHIATRIC-PATIENTS USING 3 MEASUREMENT APPROACHES

Many previous prevalence studies of polydipsia (PD) have utilized sing le and often non-biologic measures, In this study we estimated prevale nce using specific gravity of urine (SPGU), normalized diurnal weight gain (NDWG), and staff identification (staff ID), Agreement between th ese two biologic and one behavioral measure was assessed, A total of 5 72 psychiatric inpatients were assessed for SPGU and NDWG, Unit staff were asked to identify, PD patients, Positive and negative PD groups w ere formed separately based on the SPGU, NDWG, and staff ID data, All three measures were collected on the same day. Prevalence data for the biologic measures varied The estimate for PD by SPGU (<1.009 cutoff) was higher (43.4% of sample) than that of NDWG (>2.5%; 25.4%) or staff ID (21.4%), These prevalence rates did not change substantially after exclusion of medical causes of polyuria. Agreement assessed by the ka ppa statistic, was uniformly low among the measures, Weak association between the measures reflects their multidetermined, nonspecific natur e, and highlights the lack of a diagnostic standard in the field. The observed prevalence rates must be considered rough approximations. Ass ociations between the measures and certain subject characteristics sug gest the measures may identify different types of potential PD patient s, These different types of patients are discussed, as are other issue s in the measurement of PD. The data suggest estimates of PD are a fun ction of the type of measure used as even biologic measures vary great ly. (C) 1997 Society of Biological Psychiatry.