Research report
Measuring depressive symptoms using the Patient Health Questionnaire-9 in Hong Kong Chinese subjects with type 2 diabetes

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Abstract

Background

Depression is common in type 2 diabetes although the prevalence in Chinese patients remains unclear. We validated the Patient Health Questionnaire(PHQ-9), a popular depression screening tool, in Chinese with type 2 diabetes, and documented the prevalence, demographic,and clinical characteristics associated with depression.

Methods

A consecutive cohort of 586 Hong Kong Chinese outpatients completed the PHQ-9 during comprehensive diabetes complication assessment. Within 2–4 weeks, 40 patients were retested via telephone survey. Ninety-nine randomly selected patients were interviewed by psychiatrists using the Mini International Neuropsychiatric Interview as a golden standard. Receiver operating characteristic curve was used to assess performance of the PHQ-9.

Results

The internal consistency of the PHQ-9 was 0.86 and test–retest reliability was 0.70. The 3 somatic items explained 53.6% of the PHQ-9 score. The optimal cutoff value was 7 with 82.6% sensitivity and 73.7% specificity, giving a depression prevalence of 18.3% (n=107). Of these, 18.7% had been previously diagnosed with depression. Depression was more prevalent in women than men. After controlling for confounders, patients with depression had higher HbA1c (7.80±1.86% versus 7.43±1.29%, [61.7±20.4 versus 57.8±14.1 mmol/mol], P<0.05), reduced likelihood of achieving HbA1c target of <7.0% (33.6% versus 41.8%, P<0.05), and were more likely to have self-reported hypoglycemia in the previous 3 months (18.7% versus 6.7%, P<0.01).

Limitation

A small sample was used in the criterion validation and the cross-sectional design precludes causal inference.

Conclusions

PHQ-9 is a validated tool for screening for depression, which is common and frequently undiagnosed in Chinese type 2 diabetic patients and is associated with suboptimal glycemic control, hypoglycemia, and somatization.

Introduction

Depression has been recognized as a common comorbidity in patients with type 2 diabetes (Pan et al., 2010, Roy and Lloyd, 2012). Coexistent depression in type 2 diabetes is associated with poor glycemic control, functional impairment, increased risk of diabetic complications and mortality, and reduced societal productivity (Ciechanowski et al., 2000, Katon et al., 2004a, Kleine-Budde et al., 2013, Molosankwe et al., 2012, Sullivan et al., 2012, Ting et al., 2013). Given the global diabetes epidemic where 371 million people were estimated to suffer from diabetes in 2012 (International Diabetes Federation, 2012), the co-morbid impact of depression in these patients poses a substantial burden to the individual, health care system, and society at large. Yet despite the increasing recognition of co-morbid depression and type 2 diabetes, most patients remain undiagnosed or under-treated (Katon et al., 2004b). As a result, professional guidelines have recommended screening to detect mental dysfunction including depression to further optimize diabetes care (ADA, 2013, Egede and Ellis, 2010).

The 9-item Patient Health Questionnaire (PHQ-9) is one of the most popular self-administered screening tools that has been validated in many populations including the general Hong Kong Chinese population (Chen et al., 2010, Kroenke et al., 2001, Yeung et al., 2008, Yu et al., 2012). However, its psychometric properties have not been widely studied in Chinese patients with type 2 diabetes. Furthermore, despite the high prevalence of type 2 diabetes in Hong Kong (Chan et al., 2009), there is a paucity of local data about the epidemiology of depression in patients with type 2 diabetes.

Hong Kong is a unique Chinese city because of its strong Western influences, providing an opportunity to investigate the epidemiological impact of Western acculturation on depression and diabetes in Chinese subjects. Herein we validated the Chinese version of the PHQ-9 in Hong Kong Chinese patients with type 2 diabetes and determined the prevalence of depression and its association with various demographic and clinical factors in this population.

Section snippets

Subjects and setting

Between July 2010 and July 2011, we consecutively recruited Hong Kong Chinese patients with type 2 diabetes between the ages of 25 and 75 years old during outpatient comprehensive diabetes complication assessments at the Prince of Wales Hospital and Yao Chung Kit Diabetes Assessment Centre. Exclusion criteria included (1) type 1 diabetes defined as presentation with diabetic ketoacidosis, unprovoked ketosis, or requirement of insulin within 12 months of diagnosis; (2) disabling disease or

Characteristics of participants

Amongst the 601 patients who initially consented, 3 did not complete the PHQ-9 and 12 were not eligible (3 patients aged <25 years; 4 aged >75 years; 5 with type 1 diabetes). Table 1 shows characteristics of 586 eligible participants. The mean (±SD) age was 55.1±9.5 years, and 40.8% (n=239) were women. The median disease duration of 7.0 years, and 8.2% (n=48) of the patients were taking medications for mood disorder.

Validation of PHQ-9

The mean score of PHQ-9 was 3.51±4.30 (range 0–26) in the whole cohort. The

Discussion

To our knowledge, this is the first comprehensive study which systematically addressed the prevalence and characteristics of the co-occurrence of type 2 diabetes and depression in Chinese patients, which was associated with somatization, poor glycemic control and hypoglycemia.

Conclusions

The PHQ-9 is a validated tool to detect major depression in Chinese patients with type 2 diabetes. The presence of depression was prevalent, and associated with suboptimal metabolic control with strong components of somatization. In this light, the rapid socio-economic development of China with the parallel rising of diabetes and depression will need timely study to delineate this double disease burden. Given the prognostic significance of these two often silent conditions, there is an urgent

Conflict of interest

The work is original and all authors meet the criteria for authorship, including acceptance of responsibility for the scientific content of the manuscript.

J.C.N. Chan is a faculty member of the Lilly TCPV Educational Program and member of the steering committee of clinical studies sponsored by Lilly. She has received sponsorships and honorarium for giving lectures and her institution has received research grants from Lilly. The other authors declare that they have no competing interests.

No

Role of funding source

This study was supported by the European Foundation for Study of Diabetes, the Chinese Diabetes Society, Lilly Foundation, Asia Diabetes Foundation and Liao Wun Yuk Diabetes Memorial Fund, the latter under the Chinese University of Hong Kong.

Acknowledgments

We gratefully acknowledge Dr. Larry Cimino of the Dialogue on Diabetes and Depression, Ms. Rebecca Wong, nurse consultant, Ms. Harriet Chung, nurse specialist and all clinical staff concerned at the Prince of Wales Hospital for their contributions.

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