Identification of depression in diabetes: the efficacy of PHQ-9 and HADS-D

Abstract

Background: Clinical guidelines advise screening for depression in patients with diabetes. The Patient Health Questionnaire (PHQ-9) and the depression subscale of the Hospital Anxiety and Depression Scale (HADS-D) are commonly used in primary care.

Aim: To compare the efficacy of HADS-D and PHQ-9 in identifying moderate to severe depression among primary care patients with type 2 diabetes.

Design of study: Self-report postal survey, clinical records assessed by GPs.

Setting: Seven metropolitan and rural general practices in Victoria, Australia.

Method: Postal questionnaires were sent to all patients with diabetes on the registers of seven practices in Victoria. A total of 561 completed postal questionnaires were returned, giving a response rate 47%. Surveys included demographic information, and history of diabetes and depression. Participants completed both the PHQ-9 and HADS-D. Clinical data from patient records included glycosylated hemoglobin (HbA1c) levels and medications.

Results: The proportion of the total sample completing HADS-D was 96.8% compared with 82.4% for PHQ-9. Level of education was unrelated to responses on the HADS-D but was related to completion of the PHQ-9. Using complete data (n = 456) from both measures, 40 responders showed HADS-D scores in the moderate to severe range, compared with 103 cases identified by PHQ-9. Only 35 cases were classified in the moderate to severe category by both the PHQ-9 and HADS-D. Items with the highest proportions of positive responses on the PHQ-9 were related to tiredness and sleeping problems and, on the HADS-D, feeling slowed down.

Conclusion: It may be that the items contributing to the higher prevalence of moderate to severe depression using the PHQ-9 are due to diabetes-related symptoms or sleep disorders.

Figure 1

Distribution of depression severity among patients with diabetes assessed on the depression subscale of the Hospital Anxiety and Depression Scale (HADS-D, n = 543) and the Patient Health Questionnaire (PHQ-9, n = 462).

Figure 2

Distribution of responses for maximum score 3 on individual items of the depression subscale of the Hospital Anxiety and Depression Scale (HADS-D) by depression severity: minimal n = 426, mild n = 66, moderate to severe n = 51. H1–H7 refers to individual question items (see Appendices 1 and 2).

Figure 3

Distribution of responses for maximum score 3 on individual items of the Patient Health Questionnaire (PHQ-9) by depression severity: minimal n = 276, mild n = 82, moderate to severe n = 104. P1–P9 refers to individual question items (see Appendices 1 and 2).