The 12-Month Incidence and Predictors of PHQ-9–Screened Depressive Symptoms in Chinese Primary Care Patients

Weng-Yee Chin; Eric Yuk Fai Wan; Edmond Pui Hang Choi; Kit Tsui Yan Chan; Cindy Lo Kuen Lam

doi:10.1370/afm.1854

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Figure 1
Patient inclusion in the study and in regression analyses.
PHQ-9 = 9-item Patient Health Questionnaire.

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Table 1

Baseline Characteristics of Study Patients, Overall and by PHQ-9 Screening Status Over the 12-Month Follow-up

Characteristic	Total (N = 2,929)	PHQ-9 Screening Status Over 12 Months		P Value
Characteristic	Total (N = 2,929)	Negative (n = 2,782)	Positive (n = 147)	P Value
Patient factors
Sex, %				.058
Male	44.3	44.7	36.7
Female	55.7	55.3	63.3
Age, mean (SD), y	49.3 (7.0)	49.2 (16.9)	51.7 (18.2)	.08
Ethnicity, %				.68
Chinese	98.2	98.2	98.6
Non-Chinese	1.8	1.8	1.4
Marital status, %				.03
Married	65.4	65.9	57.1
All others (single, separated, divorced, widowed)	34.6	34.1	42.9
Household monthly income, %				.003
Moderate or higher income (>HK$30,000)	41.5	42.2	29.1
Lower income (≤HK$30,000)	58.5	57.8	70.9
Education level, %				.01
Secondary or tertiary education	76.6	77.1	68.0
No formal or primary education	23.4	22.9	32.0
Employment status, %				.33
Employed	65.0	65.4	56.8
Unemployed	1.2	1.2	1.4
Retired	20.9	20.6	26.7
Homemaker	10.5	10.4	12.3
Student	2.4	2.4	2.7
Smoking status, %				.08
Nonsmoker	88.2	88.4	83.7
Smoker	11.8	11.6	16.3
Drinking status, %				.94
Nondrinker	87.6	87.5	87.8
Drinker	12.4	12.5	12.2
Exercise status, %				.61
Exercise	73.7	73.6	75.5
No exercise	26.3	26.4	24.5
Number of comorbidities, %				<.001
0	48.0	48.6	37.4
1	27.4	27.6	24.5
≥2	24.6	23.9	38.1
Family history of mental illness, %				.03
Yes	90.5	90.8	85.3
No	9.5	9.2	14.7
Number of visits to a western physician in past 4 weeks, %				.02
0	51.6	51.5	53.5
1–2	38.9	39.3	31.3
≥3	9.5	9.2	15.3
Number of visits to a traditional Chinese medicine practitioner in past 4 weeks, %				.80
0	85.5	85.5	84.7
≥1	14.5	14.5	15.3
District of residence, %				.61
Hong Kong	43.3	43.1	46.6
Kowloon	23.7	23.7	24.0
New Territories	33.0	33.2	29.5
Physician factors
Sex, %				.64
Male	72.4	72.5	70.7
Female	27.6	27.5	29.3
Age, mean (SD), y	44.8 (11.8)	…	…	…
District of practice, %				.44
Hong Kong	47.9	47.7	51.7
Kowloon	30.3	30.3	30.6
New Territories	21.8	22.0	17.7
Related training, %				.07
Vocational training in family medicine only	48.8	48.4	55.8
Diploma in psychological medicine only	18.3	18.4	16.3
Both	7.8	8.0	2.7
Neither	25.2	25.2	25.2
Practice setting, %				.004
Public	29.0	28.5	39.5
Private	71.0	71.5	60.5

PHQ-9 = 9-item Patient Health Questionnaire.

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Table 2

Characteristics Associated With Incident Depressive Symptoms in Chinese Primary Care Patients (Fixed Effects)

Characteristic	Incidence Rate Ratio (95% CI)
Patient factors (2,540 patients)
Female (vs male)	1.58^a (1.05–2.37)
Age, in years	0.99 (0.97–1.01)
Non-Chinese (vs Chinese)	0.67 (0.09–5.17)
All other marital statuses (vs married)	1.45 (0.89–2.37)
Lower income, ≤HK$30,000 (vs middle or higher income, >HK$30,000)	1.56^a (1.10–2.21)
No formal or only primary education (vs secondary or tertiary education)	1.24 (0.81–1.88)
Employment status (vs employed)
Unemployed	0.84 (0.18–3.85)
Retired	1.24 (0.79–1.94)
Homemaker	0.70 (0.41–1.20)
Student	1.54 (0.50–4.80)
Smoker (vs nonsmoker)	1.73^a (1.04–2.88)
Drinker (vs nondrinker)	1.22 (0.79–1.90)
No exercise (vs exercise)	1.08 (0.80–1.45)
Comorbidities (vs 0)
1	1.16 (0.64–2.10)
≥2	1.92^a (1.18–3.13)
Family history of mental illness (vs none)	2.02^a (1.35–3.04)
Visits to a western physician in past 4 weeks (vs 0)
1–2	0.79 (0.51–1.23)
≥3	1.90^a (1.18–3.07)
Visits to a traditional Chinese medicine practitioner in past 4 weeks, any (vs none)	1.04 (0.53–2.01)
District of residence (vs Hong Kong)
Kowloon	1.14 (0.59–2.20)
New Territories	1.17 (0.61–2.27)
Physician factors (59 physicians)
Female (vs male)	0.69 (0.38–1.26)
Age, in years	1.00 (0.97–1.03)
Practice district (vs Hong Kong)
Kowloon	0.85 (0.44–1.64)
New Territories	0.69 (0.33–1.43)
Related training (vs neither)
Family medicine training	0.91 (0.49–1.72)
Diploma in psychological medicine	1.04 (0.59–1.82)
Both	0.28^a (0.09–0.89)
Private setting (vs public)	0.56 (0.30–1.07)
Time
Time, in weeks	1.02^a (1.02–1.03)

Note: 389 patients were excluded from the analysis because of missing values.
↵a Statistically significant at P <.05.

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Table 3

Model Performance in Predicting Incident Depressive Symptoms in Chinese Primary Care Patients

Measure	Value
Error variance
Intercept, patient, variance (SE)	1.46 (0.89–2.41)
Intercept, physician, variance (SE)	0.05 (0.002–1.199)
Goodness of fit
Pseudo R² (McFadden), %	18.3
Patient ICC, %	33.4
Physician ICC, %	4.9

ICC = intraclass correlation coefficient; SE = standard error.
Note: 389 patients were excluded from the analysis because of missing values.

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The Article in Brief

The 12-Month Incidence and Predictors of PHQ-9-Screened Depressive Symptoms in Chinese Primary Care Patients

Weng-Yee Chin , and colleagues

Background There have been few cohort studies (which take place over time) examining the rate of depression in primary care patients. This study estimates the occurrence of depression and risk factors associated with depression symptoms among primary care patients in Hong Kong.

What This Study Found There is a high rate of new depression symptoms in Chinese primary care patients seeking care from physicians in a Hong Kong research network. Specifically, among 2,929 adult patients, there is a 5 percent cumulative incidence of positive screening for depression. Predictors include being female, coming from a lower-income household, being a smoker, having at least two other medical conditions, having a family history of depression, and having consulted a physician at least twice in the past month. The rate of depression is lower among patients seen by physicians with qualifications in both family medicine and psychological medicine, implying the possibility of a preventive benefit of seeing clinicians with joint training.

Implications

The authors suggest that policies to enhance the training requirements of primary care physicians may help reduce the burden of depressive disorders in Hong Kong.