Low back pain is one of the most common disabling conditions worldwide [
CLBP may emerge from several different etiologies but about 40 to 50% of CLBP, treated in specialized pain or orthopedic clinics, is alleged to be of discogenic origin [
Little is known about the specific impact of CDP on patients and its burden for society. About the impact of CLBP in general, there is more information [
Therefore, the first aim of this study is to provide healthcare and societal cost information about CDP patients who have been referred to pain specialized care. The second aim is to assess the impact of CDP on patients’ pain, disability, health-related quality of life, and QALY loss.
This study is a CDP evaluation with both a cost of illness analysis and assessment of outcome [
There are two methods available to estimate costs of disease. Top-down healthcare cost data can be obtained from central data collecting sources like medical insurance agencies [
Eighty consecutive patients with CDP, as diagnosed by clinical history, physical examination, magnetic resonance imaging, and provocation discography, were eligible for the IMBI study and were included in this evaluation. Inclusion and exclusion criteria were described in detail in the study protocol of the RCT [
The baseline data used for this study included sociodemographic characteristics, pain severity and pain medication use, disability, and health-related quality of life [
Patients rated their low back pain in a pain diary, 3 times a day during 4 days, using 11 box (0–10) numeric rating scales (PNRS); zero represents no pain and 10 excruciating pain [
Physical functioning was measured with the Oswestry Disability Index (ODI) [ 0–20% minimally limited: patient can get along with most daily activities. There is normally no treatment indicated except advice about sitting, lifting, and exercises. 21–40% moderately limited: patient experiences pain when lifting, sitting, and standing. Travel and social life is sometimes difficult, and absenteeism can occur. Normally, there are no limitations in daily activities, sexual activity, or sleeping. 41–60% clearly limited: pain is problem in activities. Treatment is indicated. 61–80% very limited to disabled: back pain affects all aspects of life of the patient. Treatment is very desirable. 81–100% disabled. These patients are often bedridden.
Health-related quality of life was assessed with the Rand-36 and the EuroQol (EQ-5D-3L) [
The QALY is a composite measure which multiplies life years with the quality of these life years. One QALY represents one life year in perfect health. QALYs lived in one year were calculated based on the EQ-5D-3L at baseline, using the UK algorithm [
Health care and societal costs were measured with cost questionnaires with a recall period of 3 months, which were filled out by patients online [
The patients were asked to record the resource use specifically related to their treatment of back pain, such as visits to primary care, medical specialists, physical therapists, and complementary and alternative medicine. Furthermore, the questionnaire queried specifically about back pain-related medication costs, extra requirements such as adaptations to home or equipment for their mobility, and professional caregiving costs. Moreover, patients were asked to report societal costs that included lost productivity and informal caregiving costs. Work absenteeism was measured with the productivity and disease questionnaire (PRODISQ) [
With the exception of the pain diary and the EQ-5D-3L, which were presented to the patient in a booklet, all data were collected by web-based questionnaires software, SelectSurvey (NETv4.075.011© Copyright 2008
All costs-related information from the baseline questionnaires in which patients were asked about information covering a period of 3 months before entering the study were multiplied by 4 to calculate annual costs per patient. Study-related costs, like costs made for informed consent consults, were not included in the cost analysis. The cost of work absence (productivity losses) was calculated using the friction cost method, which assumes that each worker is replaceable within 85 workdays or 12 weeks [
In this study, we estimated the costs of absenteeism due to CDP for each patient by multiplying the total number of sick days by the mean number of daily working hours and the costs per hour [
Results are presented as means, range, and standard deviation. Costs results are presented as bootstrapped means and 95% confidence intervals of means (CI). Statistical analyses were performed using SPSS version 24 (SPSS Inc., Chicago IL, USA).
Eighty patients included in the IMBI study [
Flow diagram.
Patient characteristics.
|
Male | Female | |
---|---|---|---|
Gender, |
23 (29%) | 57 (71%) | |
Mean (SD) | Mean (SD) | Mean (SD) | |
Age (years) | 41.8 (9.9) | 41.5 (8.7) | 41.9 (10.5) |
Low back pain (0–10) | 6.5 (1.5) | 6.7 (1.7) | 6.4 (1.4) |
Pain duration (years) | 10.6 (8.0) | 9.7 (5.6) | 10.9 (8.8) |
Treatment duration (years) | 5.7 (5.7) | 3.5 (2.5) | 6.6 (6.3) |
Education, |
|||
Low | 8 (10%) | 2 (9%) | 6 (11%) |
Middle | 45 (55%) | 14 (61%) | 31 (54%) |
High | 27 (35%) | 7 (30%) | 20 (35%) |
Employment/work, |
|||
Full time | 31 | 12 (52%) | 19 (33) |
<30 hours a week | 26 | 2 (9%) | 24 (42%) |
Unemployed | 13 | 4 (17%) | 9 (16%) |
Disability payment (DIA) | 10 | 5 (22%) | 5 (9%) |
Data presented as total group and divided by gender. DIA = Disablement Insurance Act; SD = standard deviation.
Table
The mean physical limitations rate was 43.7 (SD: 14.9) as measured by the ODI [
Health-related quality of life as measured with the Rand-36 and EQ-5D-3L is shown in Table
Health-related quality of life of patients with discogenic low back pain.
Mean | Std. deviation | |
---|---|---|
|
||
Physical functioning | 48.25 | 18.25 |
Social functioning | 52.37 | 23.60 |
Role limitations physical | 15.31 | 26.23 |
Role limitations emotional | 59.16 | 43.40 |
Mental health | 65.10 | 20.08 |
Bodily pain | 32.88 | 17.22 |
Vitality | 44.62 | 17.92 |
General health | 35.62 | 20.96 |
|
32.52 | 6.05 |
|
44.67 | 10.96 |
|
||
EQ-5D overall health (VAS) | 52.51 | 17.74 |
UK utility value (EQ-5D) | 0.36 | 0.34 |
VAS = visual analogue scale.
Baseline EQ-5D health profile (percent patients’ response categories per domain).
Table
Table
Healthcare costs per CDP patient in euros divided by cost type.
Cost type |
|
|
Mean^ costs per resource user (CI) | Mean^ cost per patient |
Cum. % |
---|---|---|---|---|---|
Daycare clinic | 340 | 53 | 2,950.94 (2574–3328) | 1,955.00 (1565–2353) | 48 |
Physical therapy | 1112 | 27 | 1,475.52 (965–1986) | 461.10 (245–676) | 60 |
Travel costs | 964 | 79 | 303.03 (232–374) | 299.24 (229–370) | 67 |
Psychosocial therapy | 208 | 17 | 1,703.63 (615–2792) | 234.25 (51–417) | 73 |
Pain clinic | 888 | 60 | 292.37 (227–358) | 219.27 (163–275) | 78.5 |
CAM therapies | 224 | 10 | 1,330.80 (427–2234) | 166.35 (30–303) | 82.5 |
Medication | 126 | 67 | 172.62 (108–237) | 144.56 (89–200) | 86 |
Extra requirements | 36 | 9 | 1,128.89 (−36 to 2294) | 127.00 (−6 to 260) | 89 |
Rehabilitation | 264 | 4 | 2,524.50 (−2273 to 7322) | 126.23 (−53 to 305) | 92 |
Home care | 1056h | 37 | 3.210 (1490–5010) | 118.25 (−3 to 325) | 95 |
Occupational physician | 228 | 29 | 259.45 (173–345) | 94.05 (53–135) | 97 |
Primary care | 164 | 18 | 300.67 (220–381) | 67.65 (35–100) | 98 |
Hospital nights | 40 | 10 | 528.89 (407–651) | 59.50 (20–99) | 99 |
Policlinic other | 92 | 4 | 523.25 (−852 to 1899) | 26.16 (−19 to 72) | 99.5 |
Intensive care | 4 | 1 | 2,015 | 25.18 (−24 to 75) | 100 |
Total healthcare costs | 80 | 4,015.38 (3251–4779) | 4,015.38 (3251–4779) |
eVisits/events/services/volumes; hvolume in hours; ^bootstrapped mean;
Sixty-seven patients (84%) regularly used analgesics for their low back pain: 33% of patients regularly used paracetamol, 31% used nonsteroidal anti-inflammatory drugs, 14% used weak opioids analgesics, and 11% of patients used strong opioids. The mean yearly cost for medication was calculated at €144.56 (CI: 89–200). Approximately 80% of healthcare cost are targeted at pain therapies and related therapies like physical therapy (12%), psychosocial therapy (6%), and 4% for complementary and alternative medicine (CAM). Daycare clinic and pain clinic both made up for 53.5% of the healthcare costs.
The total mean societal costs were composed out of informal caregiving and costs related to work absence (see Table
Societal costs per patient in euros divided by cost type (results of the friction cost and human capital cost approach).
Cost type friction costs approach |
|
Mean^ costs per resource user (CI) | Mean^ cost per patient |
Cum. % |
---|---|---|---|---|
Informal caregiving | 37 | 255.68 (143–368) | 118.25 (60–177) | 3 |
Absence work; friction costs | 20 | 15,113 (11090–19135) | 3,778.32 (2038–5518) | 100 |
Societal cost per patient: Friction | 3,896.57 (2157–5636) | |||
|
||||
Informal caregiving | 37 | 255.68 (143–368) | 118.25 (60–177) | 0.8 |
Absence work; human capital | 31 | 38,212 (28520–47903) | 14,806,95 (9283–20330) | 100 |
Disability wages | 11 | 46,720 (39447–53994) | 6,424.03 (2720–10128) | |
Societal cost per patient: human capital | 14,925.20 (9389–20460) |
eNumber of patients per event/service; ^bootstrapped mean;
Using the friction cost approach, the mean annual total costs per patient with CDP were €7,911.95: €4,015.38 (51%) healthcare cost and €3,896.57 (49%) societal costs.
When the human capital cost approach is used, the total mean annual cost per CDP patient was calculated to be €18,940.58: €4,015.38 (22%) healthcare cost and €14,925.20 (78%) societal costs.
The main objective of this study was to assess the costs of CDP for patients and society. Furthermore, we assessed the impact of CDP on patients’ pain, disability, health-related quality of life, QALYs, and QALY loss.
Almost half (46%) of CDP patients reported severe pain (>7 of PNRS 0 to 10), 54% suffered moderate pain. A European prevalence study in chronic pain suffering patients showed that 34% had severe pain and 66% had moderate pain [
In this study, we found that the annual cost per patient for the society is €7,911.95: €4,015.38 (51%) healthcare cost and €3,896.57 (49%) societal costs, using the friction costs approach. Using the human capital approach, the mean cost is €18,940.58: €4,015.38 (22%) for the healthcare cost and €14,925.20 (78%) societal costs per patient.
Costs are on average 56% lower in studies using the friction cost approach than in studies using the human capital approach, because it takes into account that employees can be replaced after a certain time period, i.e., for this study, 85 workdays or 12 weeks [
The cost for disability wages (€6,424.03) was only considered in the human capital approach [
The inclusion and exclusion criteria for the RCT, from which this study retrieved information, could have an effect on the outcome considering that the patients with more than 35 BMI, or degeneration of multiple discs (>2) were excluded. Furthermore, patients with very severe disc degeneration (Grade V Modified Dallas Scale) were excluded in the RCT, and this study used data from [
In comparison, a study in rheumatoid arthritis [
The HRQoL was not only low in the scores for physical functioning but also general health and bodily pain scores were low. The mean utility value (i.e., quality of life score) based on the EQ-5D was extremely low (0.36) in the CDP patients. General population score of people in Europe around 45 years of age is approximately 0.85; for instance, a chronic low back pain population in Finland scored mean 0.74 [
The lowest scores of the Rand-36 were shown on the item “role limitations due to physical functioning” mean 15.3 (SD: 26.3) and bodily pain 32.9 (SD: 17.2). In comparison, the Dutch general population scored, respectively, 79.5 (SD: 35.4) and 80.5 (SD: 24.4) [
Our study showed that the patients with CDP in our study suffered moderate to severe pain for on average 10 years (Table
This study was performed in 4 pain centres across the Netherlands: 3 general hospitals and 1 university pain clinic. Only patients with a confirmed diagnosis of chronic discogenic low back pain were included in this study. Our study comprised 57/80 (71%) female patients. Although this seems a disproportional amount of the female gender, research shows that a larger part of the female CLBP suffering population has back pain with impairment: 70% in women versus 57% in men [
The prevalence of CLBP is estimated to be 9% [
As far as we know, this is the first study that shows the economic burden for society and the impact of CDP on patients. A comparable study with bottom-up information conducted with patients from a pain clinic showed that the total costs of chronic pain suffering patients was US$24,043 using the human capital cost approach [
On average, CDP patients are in the middle of their productive life at the age of 40, have growing up children, have to pay off mortgage and plan ahead for the studies of their children. Patients suffering low back pain tend to return to work within 6 weeks to 3 months after the acute phase of the condition [
Although many healthcare resources are used (and much money is spent each year), the patients included in this trial at baseline still suffer pain and experience loss in quality of life. Innovations and further development of effective treatments are essential to better manage CDP and diminish associated patient burden and societal costs in the future.
Society spends €7,911.95 (friction costs approach) or €18,940.58 (human capital approach) each year per CDP patient. Societal costs are for a large part caused by work absence. In patients with CDP, healthcare resources are mostly used for pain therapies. Despite these efforts, baseline patients for this study suffer severe pain, are physically limited, and experience serious loss of quality of life.
The data used to support the findings of this study are available from the corresponding author upon request.
The authors declare that they have no conflicts of interest.
The original RCT used for the present study was funded by “The Netherlands Organization for Health Research and Development” (ZonMw) (Project number 836011026_JG_CD_JG). This study sponsor has no role in, and no authority over, data collection, management, analyses, interpretation of data, writing the report, and the decision to submit the report for publication.