Association between pain severity, depression severity, and use of health care services in Japan: results of a nationwide survey

Figures & data

Table 1 Sociodemographic and health characteristics among those with depression and comorbid physical pain in Japan

	(N=352)
	N	%
Female	202	57.4
Marital status
Married or living with partner	160	45.5
Single, never married	143	40.6
Divorced	49	13.9
Annual household income
Less than ¥ 3,000,000	114	32.4
¥ 3,000,000 to ¥ 4,999,999	71	20.2
¥ 5,000,000 to ¥ 8,999,999	86	24.4
¥ 9,000,000 or more/decline to answer	81	23.0
University degree or greater	150	42.6
Employed	204	58.0
BMI categories
Underweight	56	15.9
Normal	190	54.0
Overweight	78	22.2
Obese	14	4.0
Decline to answer	14	4.0
Currently drinks	255	72.4
Currently smokes	117	33.2
Currently exercises	153	43.5
	Mean	SD
Age	41.5	12.1
BMI (N=339)	22.7	4.9
CCI	0.53	2.12

Abbreviations: BMI, body mass index; CCI, Charlson comorbidity index; SD, standard deviation.

Table 2 Depression characteristics among those with depression and comorbid physical pain in Japan

	(N=352)
	N	%
Type of diagnosing physician (N=338)
General internist	53	15.7
Psychiatrist	268	79.3
Other	17	5.0
Currently using a prescription for depression	274	77.8
Severity (self-rated)
Mild	117	33.2
Moderate	165	46.9
Severe	70	19.9
Depression severity categories (PHQ-9; N=185)
None (0–4)	13	7.0
Mild (5–9)	47	25.4
Moderate (10–14)	40	21.6
Moderately severe (15–19)	41	22.2
Severe (20–27)	44	23.8
Problems made it hard to work/function (PHQ-9; N=182)
Not difficult at all	16	8.8
Somewhat difficult	101	55.5
Very difficult	35	19.2
Extremely difficult	30	16.5
	Mean	SD
Duration of depression (years) (N=338)	7.1	7.1
PHQ-9 total score (N=185)	14.1	7.1

Abbreviations: PHQ-9, Patient Health Questionnaire; SD, standard deviation.

Table 3 Pain characteristics among those with depression and comorbid physical pain in Japan

	(N=352)
	N	%
Currently using a prescription for pain	145	41.2
Frequency of problems with pain
Daily	94	26.7
Four to six times/week	39	11.1
Two to three times/week	43	12.2
Once a week	26	7.4
Two to three times per month	44	12.5
Once a month or less	106	30.1
	Mean	SD
Severity of pain in the past week	4.1	3.1
Severity of pain right now	4.2	2.9

Note: Pain severity items are anchored by 0 (none) and 10 (as bad as you can imagine).

Abbreviation: SD, standard deviation.

Table 4 Spearman correlations between severity of pain in the past week and health outcomes

	(N=352)
	rs	P-value
MCS	−0.11	0.034
PCS	−0.22	<0.001
Health utility score (SF-6D)	−0.21	<0.001
PHQ-9 total score (N=185)	0.19	0.009
Absenteeism (%; N=191)	0.00	0.998
Presenteeism (%; N=191)	0.22	0.002
Overall work impairment (%; N=191)	0.16	0.029
Activity impairment (%)	0.20	<0.001
Health care provider visits (past 6 months)	0.22	<0.001
ER visits (prior 6 months)	0.04	0.415
Hospitalizations (prior 6 months)	0.06	0.275

Notes: Higher MCS, PCS, and health utility scores indicate better quality of life; Higher PHQ-9 scores indicate greater depressive symptoms; Higher absenteeism, presenteeism, overall work impairment, and activity impairment scores indicate more impairment.

Abbreviations: ER, emergency room; MCS, mental component summary; PCS, physical component summary; PHQ-9, Patient Health Questionnaire.

Table 5 Regression-adjusted outcomes according to severity of pain in past week

Dependent variable	Patients in regression	P-value for pain in past week	Regression-estimated outcome values at levels of pain in past week
			At 25th percentile (1/10)	At median (4/10)	At 75th percentile (7/10)
MCS	338	0.029	28.7	27.4	26.1
PCS	338	<0.001	44.8	43.1	41.3
Health utility score (SF-6D)	338	<0.001	0.579	0.561	0.542
PHQ-9 score	179	0.039	13.7	14.9	16.0
Absenteeism	183	0.903	11.6%	11.3%	11.1%
Presenteeism	183	<0.001	35.2%	42.6%	51.5%
Overall work impairment	183	0.001	40.3%	47.2%	55.3%
Activity impairment	338	<0.001	47.5%	52.9%	59.0%
Physician visits	338	<0.001	13.8	16.8	20.4
ER visits	338	0.045	0.07	0.10	0.15
Hospitalizations	338	0.016	0.4	0.7	1.4

Notes: Models predicting MCS, PCS, SF-6D, and PHQ-9 are linear; All others are negative binomial with a log link; Covariates include age, sex, marital status, household income, university education, BMI category, cigarette smoking, alcohol use, exercise, length of depression diagnosis, and CCI.

Abbreviations: BMI, body mass index; CCI, Charlson comorbidity index; ER, emergency room; MCS, mental component summary; PCS, physical component summary; PHQ-9, Patient Health Questionnaire.