Emoqol-100: Development and validation of a single question for low mood in primary care

Background Using current inventories, case-finding for low mood in primary care is important but time-consuming.

Aim We aimed to validate the diagnostic accuracy of a single question on the emotional quality of life (Emoqol-100) as a measure of depression in symptomatic patients.

Design & setting This retrospective clinical audit validating the Emoqol-100 compared with the 9-item Patient Health Questionnaire (PHQ-9) and Burns Depression Scale Today (BDST).

Method Consecutive patients with suspected low mood, seen over 22 months in a single primary care clinic by one of the authors, were eligible for this retrospective audit (n=160). The index test was the verbally asked Emoqol-100; "How is your emotional quality of life now, with 100 being perfect and 0 being the worst imaginable?" The reference standard was the PHQ-9 (n=426 visits) with a cut point of ≥10 or BDST (n=513 visits) with a cut point of ≥6.

Results The Emoqol-100 range 0-20 had a likelihood ratio (LR) of 25.2 for low mood compared to the BDST and for Emoqol-100 scores of 21-40, 41-60, 61-80 and 81-100 the likelihood ratios were 3.6, 1.7, 0.35 and 0.09 respectively. For the PHQ-9 these were 10.1, 2.9, 1.3. 0.40 and 0.2, respectively. Any score ≤ 60 is associated with a low mood.

Conclusion The Emoqol-100 appears to have high validity, so when it is low (≤ 60), it is suggestive of a high PHQ-9 or BDST score, and a mood issue probably exists. Emoqol-100 could be helpful for busy primary care and other clinicians.