Health profile of Skaraborg County 1977. A Swedish rural cross-sectional study

The cross-sectional study entitled Health Profile of Skaraborg County, 1977 (HPS 77), forms part of an evaluation of a care programme for persons suffering from high blood pressure. Concurrently with the implementation of the study, epidemiological data were collected concerning the health profile of an entire county, with the aim of facilitating comparisons between the municipalities in the county. This paper describes how the study was implemented and gives an analysis of non-participation and validity. A comparison is made between participants and non-participants with regard to record data obtained from the National Health Insurance Fund, hospital records and the register of the Temperance Board. The non-participants differ in most respects from the participants, who have a more marked pattern of disorders in their case histories. In a longitudinal non-participants analysis, participants are compared with non-participants with respect to mortality during the following four-year period. In this study the non-participants differed, in having a higher mortality rate. The validity of the questionnaire is discussed on the basis of three different analyses. The validity varied considerably, depending on the questions studied. For example, 53% of those with myocardial infarction in the questionnaire were confirmed in hospital records. This was also true for 62% of those with stroke and 49% of those with angina pectoris in a follow-up interview. Medication for hypertension was confirmed in 94%. Ten of twelve participants who reported three or more symptoms of mental disorders were confirmed at interview with a physician. Studies like HPS 77 could be useful when planning preventive as well as curative measures. Thus it is important to describe not only the implementation of the study, but also its validity and the importance of non-participation for the results presented.