Objective: To investigate the construct validity of morbidity severity scales based on routine consultation data by studying their associations with sociodemographic factors and physical health.
Study design and setting: Study participants were 11,232 English adults aged 50 years and over and 9,664 Dutch adults aged 18 years and over, and their consulting morbidity data in a 12-month period were linked to their physical health data. Consulters with any of 115 morbidities classified on four ordinal scales of severity ("chronicity," "time course," "health care use," and "patient impact") were compared to all other consulters.
Results: As hypothesized, in both countries, morbidity severity was associated with older age, female gender, more deprivation (all comparisons P< or =0.05), and poor physical health (all trends P<0.001). The estimated strengths of association of poor physical health with the highest severity category expressed as odds ratios, for each of the four scales, were 5.4 for life-threatening on the "chronicity" scale, 1.8 for time course, 2.8 for high health care use, and 3.7 for high patient impact.
Conclusions: Four scales of morbidity severity have been validated in English and Dutch settings, and they offer the potential to use simple routine consultation data as an indicator of physical health status in populations from general practice.