Morbidity and prescribing patterns for the middle-aged population of Scotland

As part of a large national survey of morbidity recording on general practice computers, morbidity and prescribing data were collected from three separate sources for more than 10,000 patients aged 45-64 years, randomly selected from 41 Scottish general practices.

To amalgamate the three sources of data to provide estimates of prevalence rates for a range of common chronic diagnoses, and of medication rates for associated repeat prescription drugs.

Forty-one Scottish general practices were selected on a geographic basis in relation to the national population distribution. Within each practice, 250 patients aged 45-64 years were selected at random. Data relating to 19 diagnoses and 40 repeat prescription drugs were extracted from the computer records of these patients and compared with information held on patients' paper records and supplied by patients in response to a postal questionnaire. After assessing the completeness and accuracy of computer-held information, the three sources of data were amalgamated according to agreed protocols.

Lifetime prevalence rates are presented for each diagnosis, broken down by sex and age group. Differences in rates between the sexes, and with change in age, were in the expected direction for all diagnoses, and were matched by corresponding differences in entitlements to repeat prescription drugs. Comparison of these lifetime rates with published prevalence rates indicates a latent pool of morbidity within the community, which ranges from 1.0 to 10.0 times the annual prevalence rate for different conditions.

The amalgamated data provide an estimate of lifetime prevalence rates for the range of conditions examined. They complement conventional morbidity statistics and have potential value in allowing the underlying management costs of specific chronic conditions to be evaluated.