Use of a cross-sectional survey to estimate outcome of health care: The example of anxiety and depression

Our study proposes that a population-based cross-sectional survey can be us ed to estimate the outcome of health care by linking general practice morbi dity records to the survey. Using the example of anxiety and depression to test this idea, we conducted a survey of an adult population registered wit h one general practice in the UK. The Hospital Anxiety and Depression (HAD) questionnaire was used to identify cases and controls. After mailing to a randomly selected adult population of 4002, there was an adjusted response rate of 66% (n = 2,606), with 416 (16%) high-score cases, 506 (19%) medium- score cases, and 1684 (65%) low-score controls. All cases were compared wit h a sample of controls (n = 450). In the 12 months before the survey, the h igh-score case group had experienced significantly higher GP contacts (n = 377 [91%] versus 354 [79%]), diagnoses for anxiety or depression (119 [29%] versus 21 [5%]), and related drug treatments (111 [27%] versus 22 [5%]) co mpared with the control sample. Most of the diagnoses and drug treatments h ad been initiated at least 9 months before the survey. The linkage between the survey and the clinical records suggested that the health outcome of pr eviously identified anxious and depressed patients was poor, with an estima ted two-thirds who will not have fully recovered within an average of 9 mon ths. This study demonstrates the potential for using cross-sectional popula tion surveys to estimate not only the need for health care but also the out come of health care. (C) 2001 Elsevier Science Inc. All rights reserved.