Burden of chronic low back pain: Association with pain severity and prescription medication use in five large European countries

Abstract

Objective: This study assessed associations between severity of, and prescription medication use for, chronic low back pain (CLBP) and health-related quality of life, health status, work productivity, and healthcare resource utilization.

Methods: This cross-sectional study utilized SF-12, EQ-5D-5L, and work productivity and activity impairment (WPAI) questionnaires, and visits to healthcare providers among adults with self-reported CLBP participating in the National Health and Wellness Survey in Germany, France, UK, Italy, and Spain. Respondents were stratified into four groups according to pain severity (mild or moderate/severe) and prescription medication use (Rx-treated or Rx-untreated). Differences between groups were estimated using generalized linear models controlling for sociodemographics and health characteristics.

Results: Of 2086 respondents with CLBP, 683 had mild pain (276 Rx-untreated, 407 Rx-treated) and 1403 had moderate/severe pain (781 Rx-untreated, 622 Rx-treated). Respondents with moderate/severe pain had significantly worse health-related quality of life (SF-12v2 physical component summary), health status (EQ-5D-5L), and both absenteeism and presenteeism compared with those with mild pain, including Rx-untreated (moderate/severe pain Rx-untreated vs. mild pain Rx-untreated, p ≤ 0.05) and Rx-treated (moderate/severe pain Rx-treated vs. mild pain Rx-treated, p ≤ 0.05) groups. Significantly more visits to healthcare providers in the last 6 months were reported for moderate/severe pain compared with mild pain for Rx-treated (least squares mean 13.01 vs. 10.93, p = 0.012) but not Rx-untreated (8.72 vs. 7.61, p = 0.072) groups. Health-related quality of life (SF-12v2 physical component summary) and health status (EQ-5D-5L), as well as absenteeism and presenteeism, were significantly worse, and healthcare utilization was significantly higher, in the moderate/severe pain Rx-treated group compared with all other groups (all p ≤ 0.05).

Conclusion: Greater severity of CLBP was associated with worse health-related quality of life, health status, and absenteeism and presenteeism, irrespective of prescription medication use. Greater severity of CLBP was associated with increased healthcare utilization in prescription medication users.

Keywords: Europe; activity impairment; chronic low back pain; health-related quality of life; healthcare resource use; work productivity impairment.

FIGURE 1

Health‐related quality of life of respondents with chronic low back pain: SF‐12v2. *Differs from mild pain Rx‐untreated, p ≤ 0.05. ^#Differs from mild pain Rx‐treated, p ≤ 0.05. ^†Differs from moderate/severe pain Rx‐untreated, p ≤ 0.05. Higher scores indicate a better quality of life. Generalized linear models specifying a normal distribution and identity function were used to assess differences in health‐related quality of life by group. PCS and MCS scores are normed to a mean of 50 and a standard deviation of 10 for the US population. Covariates included: severity/treatment group, country of residence, age, sex, marital status, education, income, employment status, alcohol use, exercise, body mass index, smoking status, anxiety diagnosis, depression diagnosis, insomnia diagnosis, diagnosed with sleep difficulties, and CCI. A total of 18 respondents had missing data and were excluded from multivariate analyses. CCI, Charlson Comorbidity Index; LS, least squares; MCS, mental component summary score; PCS, physical component summary score; Rx, prescription medication; SE, standard error; SF‐12v2, Medical Outcomes Study 12‐Item Short Form Survey Instrument version 2

FIGURE 2

Health status of respondents with chronic low back pain: (A) SF‐6D utility score, (B) EQ‐5D‐5L index value, and (C) EQ VAS. *Differs from mild pain Rx‐untreated, p ≤ 0.05. ^#Differs from mild pain Rx‐treated, p ≤ 0.05. ^†Differs from moderate/severe pain Rx‐untreated, p ≤ 0.05. Higher scores indicate better health status. The SF‐6D index has interval scoring properties and yields summary scores from 0.3 (worst health state) to 1 (best health state). The EQ‐5D‐5L ranges from −0.59 (where 0 is the value of a health state equivalent to dead, and negative values represent values as worse than dead) to 1 (the value of full health). EQ‐5D‐5L scoring used crosswalk mapping the 5L dimension scores onto the 3L value sets,, , and the UK preference‐based set of utilities (1 to −0.594) was used for all countries based on the publisher's recommendation. The EQ VAS ranges from 0 (worst imaginable health state) to 100 (best imaginable health state). Generalized linear models specifying a normal distribution and identity function assessed differences in health status by group. Covariates included: severity/treatment group, country of residence, age, sex, marital status, education, income, employment status, alcohol use, exercise, body mass index, smoking status, anxiety diagnosis, depression diagnosis, insomnia diagnosis, diagnosed with sleep difficulties, and CCI. A total of 18 respondents had missing data and were excluded from multivariate analyses. CCI, Charlson Comorbidity Index; EQ VAS, EQ visual analog scale; LS, least squares; Rx, prescription medication; SE, standard error; SF‐6D, Short Form‐6 Dimensions

FIGURE 3

Work productivity and activity impairment among respondents with chronic low back pain: WPAI‐GH. *Differs from mild pain Rx‐untreated, p ≤ 0.05. ^#Differs from mild pain Rx‐treated, p ≤ 0.05. ^†Differs from moderate/severe pain Rx‐untreated, p ≤ 0.05. Sample sizes for mild pain Rx‐untreated, mild pain Rx‐treated, moderate/severe pain Rx‐untreated, and moderate/severe pain Rx‐treated groups, respectively: absenteeism (n = 135, n = 141, n = 320, n = 191), presenteeism (n = 132, n = 128, n = 303, n = 162), overall work impairment (n = 135, n = 141, n = 320, n = 191), and activity impairment (n = 272, n = 404, n = 777, n = 615). Higher scores indicate greater impairment (worse outcome). Generalized linear models specifying a negative binomial distribution and log‐link function assessed differences in work and activity impairment by group. Covariates included: severity/treatment group, country of residence, age, sex, marital status, education, income, employment status, alcohol use, exercise, body mass index, smoking status, anxiety diagnosis, depression diagnosis, insomnia diagnosis, diagnosed with sleep difficulties, and CCI. A total of 18 respondents had missing data and were excluded from multivariate analyses. Only respondents who reported being full‐time or part‐time employed provided data for absenteeism, presenteeism, and overall work impairment, whereas all respondents completed the activity impairment question. CCI, Charlson Comorbidity Index; LS, least squares; Rx, prescription; SE, standard error; WPAI‐GH, Work Productivity and Activity Impairment‐General Health

FIGURE 4

Healthcare resource utilization in the past 6 months among respondents with chronic low back pain: number of (A) healthcare provider visits including primary care, (B) emergency room or urgent care visits, and (C) hospitalizations. *Differs from mild pain Rx‐untreated, p ≤ 0.05. ^#Differs from mild pain Rx‐treated, p ≤ 0.05. ^†Differs from moderate/severe pain Rx‐untreated, p ≤ 0.05. Higher number of visits indicates more healthcare utilization. Panel A shows the contribution of primary care visits (hashed area) to healthcare provider visits (solid area). Generalized linear models specifying a negative binomial distribution and log‐link function assessed differences in healthcare resource utilization by group. Covariates included: severity/treatment group, country of residence, age, sex, marital status, education, income, employment status, alcohol use, exercise, body mass index, smoking status, anxiety diagnosis, depression diagnosis, insomnia diagnosis, diagnosed with sleep difficulties, and CCI. A total of 18 respondents had missing data and were excluded from multivariate analyses. CCI, Charlson Comorbidity Index; LS, least squares; Rx, prescription medication; SE, standard error