Screening medical patients for distress and depression: does measurement in the clinic prior to the consultation overestimate distress measured at home?

Background
Medical patients are often screened for distress in the clinic using a questionnaire such as the Hospital Anxiety and Depression Scale (HADS) while awaiting their consultation. However, might the context of the clinic artificially inflate the distress score? To address this question we aimed to determine whether those who scored high on the HADS in the clinic remained high scorers when reassessed later at home.

Method
We analysed data collected by a distress and depression screening service for cancer out-patients. All patients had completed the HADS in the clinic (on computer or on paper) prior to their consultation. For a period, patients with a high score (total of ≥15) also completed the HADS again at home (over the telephone) 1 week later. We used these data to determine what proportion remained high scorers and the mean change in their scores. We estimated the effect of ‘regression to the mean’ on the observed change.

Results
Of the 218 high scorers in the clinic, most [158 (72.5%), 95% confidence interval (CI) 66.6–78.4] scored high at reassessment. The mean fall in the HADS total score was 1.74 (95% CI 1.09–2.39), much of which could be attributed to the estimated change over time (regression to the mean) rather than the context.

Conclusions
Pre-consultation distress screening in clinic is widely used. Reassuringly, it only modestly overestimates distress measured later at home and consequently would result in a small proportion of unnecessary further assessments. We conclude it is a reasonable and convenient strategy.