The monitoring of longer term prescriptions of antidepressants: observational study in a primary care setting.

BACKGROUND: There is little evidence to guide the frequency of review for patients taking antidepressants in the longer term. OBJECTIVES: To measure the frequency with which patients on longer term courses of antidepressants have their treatment monitored in primary care and to identify patient characteristics associated with the frequency of monitoring. METHODS: A cohort of patients who were receiving antidepressants continuously for at least two years was identified from four general practices. Data were collected from patients' general medical records. The dates of all GP consultations and whether they included a documented review of antidepressant therapy were recorded, along with patient characteristics hypothesized to influence the frequency of monitoring. RESULTS: The frequency of antidepressant review consultations and proportion of participants being reviewed during a specific year of antidepressant therapy decreased with increasing year of antidepressant therapy. Individuals who receive antidepressants for an overt mental health reason; undergo more dose and drug changes; and who are referred to the community mental health team have their antidepressant therapy reviewed more often during the first five years of antidepressant therapy. CONCLUSION: As many patients on longer term courses of antidepressants are not being appropriately reviewed, a 'chronic disease management approach' to depression in primary care is advocated.

Psychometric comparison of PHQ-9 and HADS for measuring depression severity in primary care.

BACKGROUND: The 2004 National Institute for Health and Clinical Excellence (NICE) guidelines highlight the importance of assessing severity of depression in primary care. AIM: To assess the psychometric properties of the Patient Health Questionnaire (PHQ-9) and the depression subscale of the Hospital Anxiety and Depression Scale (HADS-D) for measuring depression severity in primary care. DESIGN OF STUDY: Psychometric assessment. SETTING: Thirty-two general practices in Grampian, Scotland. METHOD: Consecutive patients referred to a primary care mental health worker completed the PHQ-9 and HADS at baseline (n = 1063) and at the end of treatment (n = 544). Data were analysed to assess reliability, robustness of factor structure, convergent/discriminant validity, convergence of severity banding, and responsiveness to change. RESULTS: Both scales demonstrated high internal consistency at baseline and end of treatment (PHQ-9 alpha = 0.83 and 0.92; HADS-D alpha = 0.84 and 0.89). One factor emerged each for the PHQ-9 (explaining 42% of variance) and HADS-D (explaining 52% of variance). Both scales converged more with each other than with the HADS anxiety (HADS-A) subscale at baseline (P<0.001) and at end of treatment (P = 0.01). Responsiveness to change was similar: effect size for PHQ-9 = 0.99 and for the HADS-D = 1. The HADS-D and PHQ-9 differed significantly in categorising severity of depression, with the PHQ-9 categorising a greater proportion of patients with moderate/severe depression (P<0.001). CONCLUSION: The HADS-D and PHQ-9 demonstrated reliability, convergent/discriminant validity, and responsiveness to change. However, they differed considerably in how they catergorised severity. Given that treatment decisions are made on the basis of severity, further work is needed to assess the validity of the scales' severity cut-off bands.

Differential item functioning of the HADS and PHQ-9: an investigation of age, gender and educational background in a clinical UK primary care sample.

BACKGROUND: The Patient Health Questionnaire (PHQ-9) and Hospital Anxiety and Depression Scale (HADS) are commonly used measures in clinical practice and research. It is important that such scales measure the trait they purport to measure and that the impact of other measurement artefacts is minimal. Differential item functioning of these scales by gender, educational background and age is currently assessed. METHODS: Severity of depression and anxiety symptoms were measured in primary care patients referred to mental health workers using the PHQ-9 and HADS. Each scale was assessed for Differential Item Functioning (DIF) and Differential Test Function (DTF) by gender, educational background and age. Minimum n per analysis=895. DIF was assessed with Mantel's χ(2), Liu-Agresti cumulative common odds ratio (LA LOR) and the standardised LA LOR (LA LOR-Z). DTF was assessed in relation to ν(2). RESULTS: PHQ-9, HADS Depression Sub-scale (HADS-D) and HADS Anxiety Subscale (HADS-A) lacked bias in terms of gender and educational background (ν(2)<0.07). However, both PHQ-9 and HADS-D exhibited bias with regard to age: PHQ-9 ν(2)=0.103 (medium effect); HADS-D ν(2)=0.214 (large effect). PHQ-9 items exhibiting DIF by age covered: anhedonia, energy and low mood. HADS-D items exhibiting DIF by age covered psychomotor retardation and interest in appearance. LIMITATIONS: No assessment of other potential DIF contributors was made. CONCLUSIONS: PHQ-9, HADS-D and HADS-A generally do not exhibit bias for gender and educational background. However bias was observed in PHQ-9 and HADS-D for age. Caution should be exercised interpreting scores both in clinical practice and research.

Psychometric properties of the Quick Inventory of Depressive Symptomatology (QIDS-SR) in UK primary care.

It is widely believed that severity of depressive disorder should guide treatment selection and many guidelines emphasise this factor. The Quick Inventory of Depressive Symptomatology (QID-SR16) is a self-complete measure of depression severity which includes all DSM-IV criterion symptoms for major depressive disorder. The object of this study was to assess the psychometric properties of the QIDS-SR16 in a primary care sample. Adult primary care patients completed the QIDS-SR16 and were assessed by a psychiatrist (blind to QIDS-SR16) with the 17-item Hamilton Rating Scale for Depression (GRID-HAMD). Internal consistency, homogeneity and convergent and discriminant validity of the QIDS-SR16 were assessed. Severity cut-off scores for QIDS-SR16 were assessed for convergence with HRSD-17 cut-offs. Published methods for converting scores to HRSD-17 were also assessed. Two hundred and eighty-six patients participated: mean age = 49.5 (s.d. = 13.8), 68% female, mean HRSD-17 = 12.6 (s.d. = 7.6). The QIDS-SR16 exhibited acceptable internal consistency (Cronbach's alpha = 0.86), a robust factor structure indicating one underlying dimension and correlated highly with the HRSD-17 (r = 0.79) but differed significantly in how it categorised the severity of depression relative to the HRSD-17 (Wilcoxon Signed Rank Test p < 0.001). Using published methods to convert QIDS-SR16 scores to HRSD-17 scores did not result in alignment of severity categorisation. In conclusion, psychometric properties of the QIDS-SR16 were found to be strong in terms of internal consistency, factor structure and convergent and discriminant validity. Using conventional scoring and conversion methods the scale was found not to concur with the HRSD-17 in categorising the severity of depressive symptoms.

Recognition and subsequent treatment of patients with sub-threshold symptoms of depression in primary care.

BACKGROUND: Non-psychiatric physicians are better at correctly ruling out depressive disorders than appropriately recognising them. However, given large numbers of non-depressed patients, a small percentage of false positives equates to a greater number of patients than the number of depressed patients that GPs fail to detect. Concern thus arises that substantial numbers of patients with falsely identified depression may receive inappropriate interventions. METHODS: Unselected GP consulters were screened with the Hospital Anxiety and Depression Scale (HADS). GPs' perceptions of depression were independently rated on an ICD-10 scale. Case records were reviewed. Analysis related to participants with HADS-D<8. Data were assessed of 660 participants with sub-threshold symptoms. Factors were assessed according to GP ratings. RESULTS: GP perceived depression in false positive cases were more likely at index visit, to have a mental health presenting problem (OR=6.74 (95% CI=3.21, 14.16); receive antidepressant prescriptions (OR 3.79 (95% CI=1.69, 8.49) and have greater severity of HADS-D score (OR 1.18 (95% CI=1.01, 1.38). Subthreshold cases that GPs identified as depressed, more often had a recording, over subsequent six months, of: depressive symptoms (16 (35%) versus 26 (7%), p<0.001); antidepressant prescriptions (11 (24%) versus 25 (7%), p=0.001); and Community Mental Health Team referrals (4 (9%) versus 1 (<1%), p=0.001). They also consulted GPs more frequently than those not identified (median=5 (IQR 2.8, 6.3) versus median=3 (IQR=2, 5), p=0.004 over six months. LIMITATIONS: The HADS is not a diagnostic tool. CONCLUSIONS: GPs' diagnoses of depressive disorder in patients with sub-threshold symptoms were appropriate. Interventions offered to this group were consistent with documented previous histories.

Measuring depression severity in general practice: discriminatory performance of the PHQ-9, HADS-D, and BDI-II.

BACKGROUND: The UK Quality and Outcomes Framework (QOF) rewards practices for measuring symptom severity in patients with depression, but the endorsed scales have not been comprehensively validated for this purpose. AIM: To assess the discriminatory performance of the QOF depression severity measures. DESIGN AND SETTING: Psychometric assessment in nine Scottish general practices. METHOD: Adult primary care patients diagnosed with depression were invited to participate. The HADS-D, PHQ-9, and BDI-II were assessed against the HRSD-17 interview. Discriminatory performance was determined relative to the HRSD-17 cut-offs for symptoms of at least moderate severity, as per criteria set by the American Psychiatric Association (APA) and NICE. Receiver operating characteristic curves were plotted and area under the curve (AUC), sensitivity, specificity, and likelihood ratios (LRs) calculated. RESULTS: A total of 267 were recruited per protocol, mean age = 49.8 years (standard deviation [SD] = 14.1), 70% female, mean HRSD-17=12.6 (SD = 7.62, range = 0-34). For APA criteria, AUCs were: HADS-D = 0.84; PHQ-9 = 0.90; and BDI-II = 0.86. Optimal sensitivity and specificity were reached where HADS-D ≥9 (74%, 76%); PHQ-9 ≥12 (77%, 79%), and BDI-II ≥23 (74%, 75%). For NICE criteria: HADS-D AUC = 0.89; PHQ-9 AUC = 0.93; and BDI-II AUC = 0.90. Optimal sensitivity and specificity were reached where HADS-D ≥10 (82%, 75%), PHQ-9 ≥15 (89%, 83%), and BDI-II ≥28 (83%, 80%). LRs did not provide evidence of sufficient accuracy for clinical use. CONCLUSION: As selecting treatment according to depression severity is informed by an evidence base derived from trials using HRSD-17, and none of the measures tested aligned adequately with that tool, they are inappropriate for use.

Appropriateness of antidepressant prescribing: an observational study in a Scottish primary-care setting.

BACKGROUND: Since the 1990s, Scottish community-based antidepressant prescribing has increased substantially. AIM: To assess whether GPs prescribe antidepressants appropriately. DESIGN OF STUDY: Observational study of adults (aged >/=16 years) screened with the Hospital Anxiety and Depression Scale (HADS) attending a GP. SETTING: Four practices in Grampian, Scotland. METHOD: Patients (n = 898) completed the HADS, and GPs independently estimated depression status. Notes were scrutinised for evidence of antidepressant use, and the appropriateness of prescribing was assessed. RESULTS: A total of 237 (26%) participants had HADS scores indicating 'possible' (15%) or 'probable' (11%) depression. The proportion of participants rated as depressed by their GP differed significantly by HADS depression subscale scores. Odds ratio for 'possible' versus 'no' depression was 3.54 (95% confidence interval [CI] = 2.17 to 5.76, P<0.001); and for 'probable' versus 'possible' depression was 3.59 (95% CI = 2.06 to 6.26, P<0.001). Similarly, the proportion of participants receiving antidepressants differed significantly by HADS score. Odds ratio for 'possible' versus 'no' depression was 2.79 (95% CI = 1.70 to 4.58, P<0.001); and for 'probable' versus 'possible' was 2.12 (95% CI = 1.21 to 3.70, P = 0.009). In 101 participants with 'probable' depression, GPs recognised 53 (52%) participants as having a clinically significant depression. Inappropriate initiation of antidepressant treatment occurred very infrequently. Prescribing to participants who were not symptomatic was accounted for by the treatment of pain, anxiety, or relapse prevention, and for ongoing treatment of previously identified depression. CONCLUSION: There was little evidence of prescribing without relevant indication. Around half of patients with significant symptoms were not identified by their GP as suffering from a depressive disorder: this varied inversely with severity ratings. Rather than prescribing indiscriminately (as has been widely assumed), it is likely that GPs are initiating antidepressant treatment conservatively.