Back pain and depressive symptoms: A systematic review and meta-analysis

Abstract

Background

Low back pain is a common disorder that has many consequences. This study is an attempt to meta-analyze the risk of depression symptoms in back pain.

Method

Four databases were selected for review, and this search was conducted using key words. Eleven eligible articles were selected for review and meta-analysis was conducted. Subgroup analyses were continued with study design and the method of measuring depression. Also, the heterogeneity and publication bias were examined.

Results

Eleven cohort and cross-sectional articles are used in the meta-analysis between back pain and depressive symptoms. The odds ratio 2.07 was calculated for this relationship. In prospective-cohort studies, 1.71 (95% confidence interval = 1.24–2.36) results indicated that back pain is a risk factor for depression symptoms and in cross-sectional studies, pooled odds ratio (2.33; 95% confidence interval = 1.29–4.21) showed that back pain is associated with depression symptoms. Some degree of publication bias was not found in the study.

Conclusions

Back pain is an effective factor in increasing the likelihood of depression. Adoption of effective prevention and treatment approaches can play an important role in reducing the psychological consequences in these individuals.

Keywords

depression symptoms back pain meta-analysis

Introduction

Depression is a major cause of disability worldwide.¹ The lifetime prevalence of depression varies for men and women, ranging from 7% to 25%, and women have a higher prevalence of depression.² Studies have investigated the prevalence of depression and its symptoms in different populations including in the community,³ older adults,^4–6 and in different countries.⁷ The prevalence of depression has also been studied in different populations of patients such as cancer patients,^8,9 outpatients,¹ patients with digestive system diseases,¹⁰ and patients with chronic pain.¹¹ Efforts have been done to identify the predictors of depression.

Low back pain (LBP) is one of the most common occupational health problems worldwide, which leads to many socioeconomic consequences.^12,13 More than 70% of the general population in industrialized countries experience LBP during some periods of their lives.¹⁴ The prevalence of LBP during prolonged periods shows an unstable rate.^15,16 The one-month prevalence of LBP is estimated as 30% to 40%,^17,18 the 12-month prevalence is 25% to 60%,^17,19 the lifetime prevalence is approximately 80%,^20,21 and the number for chronic LBP is 10% to 13%.¹⁵ Some studies have ranked LBP as one of the main causes of the burden of disease.²² LBP is a factor in increasing the economic and health problems.²³ LBP is the first cause of occupational disability, and it affects the majority of adults²⁴ and is the most common type of musculoskeletal pain that causes disability in affected people²⁵ and can lead to chronic disabilities, reduced quality of life, economic and emotional problems, and many other disabilities.^26–32

Psychological factors play a role in the formation of disability and LBP.^33,34 According to studies and guidelines on LBP, psychological factors, especially depression, can affect rehabilitation of patients and health outcomes.^35–37 Many studies have examined the effects of depression in the onset or exacerbation of LBP.^38–46 Several meta-analytic studies have also examined the effects of depression on LBP and showed the role of this disorder in suffering from LBP.^47,48 There is evidence to suggest that LBP treatment can improve depression symptoms.^49,50 A review study on the treatment of depression in people with back pain has shown that these patients may have good therapeutic responses to psychological treatment and medication therapies.⁵¹ Depression can affect the onset of back pain or worsening it, and on the other hand, back pain can trigger depression and exacerbate it. However, studies that examine the effect of back pain on depression are very small, and more importantly, there is no meta-analysis in this area to show LBP effects on depressive symptoms. Based on this, and considering the importance of studying the psychological effects of back pain, this study is an attempt to meta-analyze the risk of depression symptoms in back pain.

Method

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)⁵² was a framework for meta-analysis and PRISMA’s statement consists of a 27-item checklist and a flow diagram which are designed to reach a better performance of systematic reviews and meta-analytic studies.⁵³ This statement is also helpful in evaluating the published systematic review articles; but this is not a tool for the quality measurement of systematic review.⁵³

Databases

The four databases listed were selected for review, and this search was conducted using key words. Online English articles until February 2018 were eligible for review, and also related article references were reviewed.

Inclusion and exclusion

Inclusion aspects include (1) prospective-cohort, cross-sectional, and case-control studies; (2) back pain as exposure; (3) depressive symptoms as outcome; and (4) studies reported indicators for association of back pain with study outcome. Exclusion aspects include (1) studies with research designs other than those mentioned above; (2) populations with physical and mental problems; (3) published articles with mixed exposure or outcomes were excluded; and (4) studies with sample size less than 100 participants.

The data were collected to further analyze the relationship between back pain and depression symptoms. The data that the authors of the current article extracted are in Table 1, which includes authors’ specifications up to the dimensions of back pain, depressive symptoms, and results between this back pain and depressive symptoms.

Table 1.

Studies included in the meta-analysis.

Studies	Country	Study design	Age range	Sex	Sample size in analysis	Back pain definition and measure	Depression measure	Quality assessment: risk of bias						Results	Adjustment for other covariates
Studies	Country	Study design	Age range	Sex	Sample size in analysis	Back pain definition and measure	Depression measure	Selection	Study design	Confounders	Blinding	Data collection method	Withdrawals/dropouts	Results	Adjustment for other covariates
Awale et al.⁶⁵	United States	Cross-sectional	66 ± 10	Both %55.8 women	2138	Back pain Self-reported	Center for Epidemiologic Studies Depression Scale	Moderate	Moderate	Moderate	Moderate	Low	Moderate	OR Men 1.33 (CI 0.88–1.77)^a Women 1.49 (CI 1.17–1.80)^a	Age, BMI
Bener et al.⁶⁶	Qatar, UnitedArab Emirates	Cross-sectional	15–65	Both %47.1 women	2180	LBP Self-reported	Patient Health Questionnaire-9	Moderate	Moderate	Moderate	Moderate	Low	Moderate	OR 1.80 (CI 1.54–2.10)^a	Matched based on age and not having cognitive impairment
Currie and Wang²⁹	Canada	Cross-sectional	≥12	Both %52.9 women	118,533	Chronic back pain Self-reported	CIDI-SFMD	Low	Moderate	Low	Moderate	Low	Moderate	OR 6.17 (CI 5.16–7.58)	Sex, age, marital status, income, education, employment, race, medical comorbidity
Currie and Wang⁶⁰	Canada	Prospective-cohort	≥15 At baseline	Both %52 women	9909	Chronic back pain Self-reported	CIDI-SFMD	Low	Moderate	Low	Moderate	Low	Low	OR 1.51 (CI 1.09–2.07)	Age, sex, self-rated health status
Gerrits et al.⁶¹	Netherlands	Prospective-cohort	18–65	Both %39.3 women	614	Back pain w	Composite International Diagnostic Interview	Moderate	Moderate	Low	Moderate	Low	Moderate	HR 2.63 (CI 1.47–4.68)	Age, gender, years of education, number of chronic diseases
Gutke et al.⁶²	Sweden	Prospective-cohort	26–32 percentile	Women	267	Lumbar pain Self-reported	Edinburgh Postnatal Depression Scale	Moderate	Moderate	Moderate	Moderate	Low	Moderate	OR 5.81 (CI 2.16–15.63)	parity, urine leakage, BMI
López-López et al.⁶⁸	Spain	Case-control	18–64	Both %56.7 women	164	Acute LBP Self-reported	Beck Depression Inventory	High	Moderate	High	High	Low	Moderate	OR Mild depression 0.35 (CI 0.19–0.68) depression 0.88 (CI 0.43–1.79) moderate depression 2.12 (CI 1.07–4.18) serious depression 18.82 (CI 1.06–331.81) extremely pronounced depression 3.03 (CI 0.12–75.64)	Unadjusted
McWilliams et al.⁶⁷	United States	Cross-sectional	25–74	Both %56.5 women	3032	Chronic back pain Self-reported	Composite International Diagnostic Interview-Short Form	High	Moderate	Low	Moderate	Low	Moderate	OR 1.40 (CI 1.08–1.82)	gender, race, education, age, other pain conditions, presence of other medical conditions
Meyer et al.⁶³	United States	Prospective-cohort	≥65	Both %56.6 women	91,347	LBP Self-reported	SF-36 Health Survey Questionnaire	Low	Moderate	Low	Moderate	Low	Moderate	OR All of the time 1.84 (CI 1.63–2.08) Most of the time 1.64 (CI 1.49–1.80) Some of the time 1.53 (CI 1.43–1.64) A little of the time 1.27 (CI 1.20–1.36)	level of depressive symptoms at baseline, age, gender, race, educational level, arthritis hand or wrist, smoking status, functional limitations, interaction term between functional limitations and gender
Mirzamani et al.⁶⁹	Iran	Case-control	15–70	Both %36.6 women	112	LBP Clinical diagnostic	Symptoms Checklist-90-Revised	High	Moderate	Low	Moderate	Low	Moderate	OR 10.27 (CI 4.91–21.49)^a	Matched based on age and marital status
Bildt et al.⁶⁴	Sweden	Prospective-cohort	18–65	Both %47.1 women	420	Chronic back pain sought medical consultation and treatment from a doctor	Interview based on the Diagnostic and Statistical Manual of Mental Disorders	Moderate	Moderate	Moderate	Moderate	Low	Moderate	OR Men 0.8 (0.8–3.9) Women 1.3 (CI 0.3–5.1)	Age

CI: confidence interval; CIDI-SFMD: Composite International Diagnostic Interview—Short Form for Major Depression; LBP: low back pain; BMI: body mass index; HR: hazard ratio; OR: odds ratio; SF: short form.

^aCalculated by authors.

Quality measure

Quality of articles was assessed according to EPHPPC⁵⁴ and was independently conducted by the authors. This assessment includes adapted six dimensions for current meta-analysis.

Meta-analysis

Studies that assessed depression based on interviews, medical records, clinical diagnoses, and self-reports were eligible for entering into the study. In some studies, pooled odds ratio (OR) was calculated using fixed-effects method. In the studies in which OR was not calculated, the authors calculated it themselves. Subgroup analyses were continued with study design and the method of measuring depression. Due to the low sex-specific and back pain groups (acute and chronic) results, this type of analysis was not possible to provide. Significance Q test indicates heterogeneity and another test for this is I².^55,56 In the following analysis of the meta-analysis data, 11 selected studies were reviewed for publication bias. At first, the funnel plot was drawn, and an evaluation of the publication bias status was performed. In the next step, the significance of the two statistical tests (Beeg and Egger) was examined, which, if were significant, is a sign of a publication bias. Finally, the trim-and-fill method^57–59 was used to determine how many studies were missing in the meta-analysis. Stata-14 software was used in order to analyze the results (Stata Corp., College Station, TX).

Result

Included and excluded studies

A search of four databases led to 2517 online published articles (see Figure 1 for more details). Screening steps were taken to obtain qualified articles and with excluding 2470 studies, 50 articles in association between back pain and mental disorders were screened. After reviewing and excluding 32 articles based on studies with review designs, other exposures, and meta-analysis studies, 18 eligible articles remained. Two studies were removed because of mixed exposure and outcome. One study was excluded due to not having a reference group. Two studies were not included due to inadequate results. Two studies were also excluded due to not providing the necessary data after contacting the authors. All studies that examined the OR of depressive symptoms in back pain were analyzed. Five cohort studies^60–64 and six cross-sectional^29,65–69 were also analyzed (Table 1).

Quality of articles

The qualitative evaluation of the studies is listed in Table 1 on the basis of the six dimensions that bias in each dimension comprises three modes: low bias, moderate bias, and high bias.

Back pain and depressive symptoms

OR was measured for back pain and depressive symptoms in the first step. Figure 2 indicates the results of pooled OR. Pooled OR (2.07; 95% confidence interval (CI) = 1.49–2.88 and P < 001) expressed a remarkable association between back pain and depressive symptoms.

Subgroup analysis

Forest plot of back pain and OR of depressive symptoms were shown in Figure 3. According to prospective cohort studies, as pooled OR (1.71; 95% CI = 1.24–2.36 and P = 0.001) indicated, back pain is a risk factor for depressive symptoms. Considering pooled OR (2.33; 95% CI = 1.29–4.21 and P < 0.005), back pain is associated with depressive symptoms in cross-sectional studies (including case-control studies). In prospective-cohort studies, the heterogeneity’s degree was reduced to a low level.⁷⁰

Figure 4 indicates the results of subgroup analysis based on depressive symptoms measure. Considering pooled OR (2.02; 95% CI = 0.91–4.47 and P = 0.082), back pain is not associated with depressive symptoms in interview-based measure of depression. Back pain is associated with depressive symptoms in questionnaire-based measure of depression due to pooled OR (1.79; 95% CI = 1.38–2.33 and P < 001). Although it was still at a high level, the degree of heterogeneity was decreased in questionnaire-based studies.⁷⁰

Publication bias

Funnel plot of back pain and OR of depressive symptoms in 11 studies are shown in Figure 5. Begg test (P = 0.312) and Egger test (P = 0.247) were nonsignificant. Therefore, the publication bias was rejected on the basis of these two tests. In the trim-and-fill method,⁵⁹ two studies must be included to make symmetry. The heterogeneity of 11 studies showed that I² was 96.1% which expresses a high degree of heterogeneity.⁷⁰ The heterogeneity was decreased in both studies by subgroup analysis based on the study design (prospective-cohort and cross-sectional), especially in prospective-cohort study design.

Discussion

Back pain affects a large part of the population.^71–75 Given the importance and potential role of back pain in the emergence and exacerbation of psychiatric disorders, especially depression, this study is an attempt to meta-analyze the risk of depressive symptoms in back pain.

The results of this study showed that the amount of depressive symptoms in people with back pain is higher; in other words, back pain is associated with an increased risk of depressive symptoms. The meta-analytic results of longitudinal studies^60–64 also indicated that back pain is associated with an increased risk of depressive symptoms over time at the baseline. An implicit implication of this finding is that it can reduce the risk of depressive symptoms in people with back pain through psychological treatments and the use of medication, as studies show the effectiveness of these interventions.^49–51 Meta-analysis of the cross-sectional studies^29,65–69 also gave similar results; however, in these studies, compared to longitudinal studies, the OR of depressive symptoms was more than doubled. It should be noted that due to the nature of cross-sectional studies, the inference of causal relationships is impossible, while in the longitudinal studies, causal relationships are more reliable. The study of the relationship between back pain and depressive symptoms based on the method of measuring depression indicated that the OR of depressive symptoms was higher based on the interview-based method than the questionnaire, and the OR was close to two. Since interviewing is a more reliable way to measure depression, these results are remarkable.

These are the strengths of the current meta-analysis, and researchers conducted a meta-analysis of the risk of depressive symptoms in people with back pain. To better understand the relationship between back pain and symptoms of depression, only those studies that were partially controlled for covariance variable in the relationship between these two variables were included into meta-analysis, except for one study. The relationship between back pain and depressive symptoms in men and women is something that could not be investigated in this meta-analysis. Subgroup analyses did not include back pain severity and severity of depressive symptoms. Most studies were cross-sectional, limiting the relationship between back pain and depressive symptoms. Heterogeneity is another issue that has encountered this meta-analysis.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Footnotes

ORCID iD

Sohrab Amiri

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