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Cost-effectiveness of combined manipulation, stabilizing exercises, and physician consultation compared to physician consultation alone for chronic low back pain: a prospective randomized trial with 2-year follow-up |
Niemisto L, Rissanen P, Sarna S, Lahtinen Suopanki T, Lindgren K A, Hurri H |
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Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology The study compared two treatment options for patients suffering from chronic low back pain (cLBP). The alternatives were:
a combination of spinal manipulation, stabilising exercises and physician consultation, and
physician consultation alone.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised employed patients aged between 24 and 46 years who were suffering from cLBP (with or without sciatica) and had an Oswestry Disability Index (ODI) of at least 16%. Patients with previous spinal operation, severe sciatica in the straight-leg-raising test with less than 35 degrees, or damaged general condition (e.g. inflammatory or malignant state or recent vertebral fracture) for which manipulation could not be recommended, were excluded from the study.
Setting The setting was primary care and the community. The economic study was carried out in Finland.
Dates to which data relate It was not reported when the effectiveness data were collected. The effectiveness data were derived from a clinical study published in 2003. The cost data were based on sources from the year 2000 and all costs were reported for the price year 2002.
Source of effectiveness data The effectiveness data were derived from a single study.
Link between effectiveness and cost data The costing appears to have been carried out prospectively on the same sample of patients as that used in the effectiveness study.
Study sample The sample size was not determined in the planning phase of the study. In addition, power calculations were not performed retrospectively on the existing sample. The study sample was initially selected on the basis of anamnestic criteria. From the initial sample size of 210 patients, six were excluded after examination by a physician. Of the 204 patients who participated in the study, 102 were assigned to the combination group and 102 to the consultation group.
Study design The analysis was based on a single-centre randomised controlled trial (RCT). The patients were followed up for a total of 2 years through questionnaires administered during physicians' visits at the initial examination before randomisation, at the 5-month follow-up examination, and 12 and 24 months after randomisation. It was reported that before the end of the 2-year period, 42 (20%) of the 204 participants (i.e. 20 in the combination group and 22 in the consultation group) dropped out. Six of these patients could not be traced and 36 did not return the questionnaire for various reasons (not reported in the paper).
Analysis of effectiveness The analysis was conducted on an intention to treat basis. The authors reported that the patient groups were comparable in their socio-demographic characteristics (age, gender and level of education), smoking habits, duration and localisation of LBP, pain intensity, self-rated disability, depression and HRQOL. The primary health outcomes used in the analysis were pain intensity and back-specific disability. The degree of pain and disability was evaluated using a visual analogue scale (VAS) (range: 0 to 100), frequency of LBP, and the ODI (range: 0 to 100). Further outcomes assessed, which were not combined with the costs, were the number of days of sick leave and patient satisfaction with care. HRQOL was evaluated using the 15D Quality of Life Instrument. It was reported that sub-scales of the 15D (HRQOL) for the two patient groups were compared with those of average 24- to 54-year-old Finns in the general population.
Effectiveness results At the end of 2 years, the score for pain intensity on the VAS was 30.7 (standard deviation, SD=24.4) in the combination group and 33.1 (SD=24.9) in the consultation alone group. The difference was statistically significant, (p=0.01).
The results for self-rated disability did not differ significantly between the two groups.
The proportion of daily LBP decreased from 58% to 23%, (p<0.001, McNemar symmetry chi-squared test) in the combination group and from 62% to 24%, (p<0.001), in the consultation group. The proportion of patients using analgesics for back pain decreased from 32% to 15% in the combination group and from 36% to 15% in the consultation group.
HRQOL increased equally in both groups, (p<0.001), without any differences in any of the 15D dimensions between groups.
The annual number of days of sick leave decreased, on average, by 5 during the 2-year follow-up period in the consultation group and by 2 in the combination group.
Results on satisfaction with care were not reported.
Clinical conclusions In terms of the health outcomes, it appears that both groups have demonstrated significant progress on self-rated outcome measurements during the study period, the combination group showing only a slightly more significant reduction in the VAS.
Measure of benefits used in the economic analysis The authors used VAS and ODI improvements as measures of benefit in the economic analysis.
Direct costs The authors compared health service costs between two periods (12 months before randomisation, and during the 24-month study period after randomisation). In the first period, the costs included were for visits to physician, visits for physiotherapy or other therapies, and other health care costs (e.g. visits to outpatient clinics, inpatient care in hospitals and X-ray examinations). During the study period, the costs included were for visits to physicians, visits for physiotherapy and other therapies, outpatient clinics visits, inpatient hospital care, X-ray examinations, and costs incurred by the patient (drugs and travel costs due to back pain).
The quantities of resources used were based on actual data derived from questionnaires administered to the study population before randomisation, and at the 12- and 24-month follow-ups. The costs and the quantities were only reported separately for visits to physicians, physiotherapy and other therapies; the authors reported summary costs in other cost categories. It was reported that service fees incurred by the patients were not included in the cost analysis. The costs were based on official actual data from the year 2000. They were reported for the price year 2002 but no adjustments for inflation were reported. The costs were not discounted.
Statistical analysis of costs A statistical analysis of the costs was conducted. First, missing cost values were assumed to be zero given that the same cost items were included in another patient's questionnaire. The authors reported mean values and SDs for all cost data, while the 95% confidence interval (CI) was estimated for total costs.
Indirect Costs The authors included productivity losses of absenteeism from work due to low back pain. The costs and the quantities were reported separately. The cost estimates were derived using actual data for the year 2000. Productivity losses due to absence from work were based on actual data and were quantified through questionnaires administered to the study population before randomisation, and at the 12- and 24-month follow-ups. The price year was 2002 but no adjustments for inflation were reported.
Currency US dollars ($). Converted from Euros at the rate $1.00 = EUR 1.01 (September 2002).
Sensitivity analysis The authors conducted a multi-way sensitivity analysis to investigate uncertainty around point estimates of incremental costs, effectiveness and cost-effectiveness ratios. Bootstrapping was carried out using R 2.0.1 software (The R Foundation for Statistical Computing Version 2.0.1; www.r-project.org), and 5,000 replica data were formed.
Estimated benefits used in the economic analysis An incremental analysis was performed. The combination group demonstrated an improvement of 1.24 (SD=2.13) in the disability ODI compared with the consultation group. The incremental effectiveness in the VAS was 4.97 (SD=5.24) compared with the consultation group.
Cost results When whole-day salary instead of half-day salary was taken into account for productivity losses, the annual mean total costs in the combination group were $2,550 before randomisation and $2,262 during the 2-year follow-up period. Thus, the decrease in the annual total costs was $288.
In the consultation group, the annual mean total costs were $3,574 before randomisation and $2,280 during the 2-year study period. Thus, the decrease in the annual total costs was $1,294.
The bootstrap analysis demonstrated that the combination group resulted in incremental cost of $1,662 (+/- 907) (95% CI: 1,637 to 1,687) compared with the consultation group.
Synthesis of costs and benefits An incremental cost-effectiveness analysis was performed. When the combination group was compared with the consultation group, it was demonstrated that a 1-point improvement in the VAS score resulted in an incremental cost of $512 (95% CI: 77 to 949).
The cost-effectiveness plane and acceptability curve demonstrated that combination therapy becomes cost-effective in 75% of bootstrapping data at a willingness-to-pay for a 1-point improvement in VAS of highest $2,100.
For the ODI, if the willingness-to-pay is $4,200, the combination therapy becomes cost-effective in 65% of bootstrapping data.
Authors' conclusions Physician consultation alone was more cost-effective than combination treatment.
CRD COMMENTARY - Selection of comparators The study compared combined manipulative treatment, stabilising exercises and physician consultation with physician consultation alone. It was unclear why the comparators used were chosen, as the authors did not justify their choice. You should decide if this represents a valid comparator in your own setting.
Validity of estimate of measure of effectiveness The analysis was based on a single-centre RCT, which was appropriate given the study question. The study sample was representative of the study population and the patient groups were shown to be comparable at analysis. The method of randomisation was not reported in the current study. However, the length of the study and loss to follow-up were all reported, suggesting that the internal validity of the study is likely to be good. The analysis was based on intention to treat and extensive statistical analyses accounted for potential biases and confounding factors. Power calculations were not reported, thus, it was not possible to ascertain whether the results obtained were due to the intervention or to chance.
Validity of estimate of measure of benefit The authors used pain intensity (measured using a VAS) and functional status - disability (measured using the ODI) at baseline and over the 2-year period. HRQOL was not used as a measure of benefit, owing to the large number of missing values at baseline.
Validity of estimate of costs The analysis of the costs was performed from a societal perspective. Although the indirect costs were appropriately included in the analysis, service fees paid by the patient were not considered, and it remains unknown to what extent their omission has affected the authors' conclusions. The quantities were not reported separately for most cost categories in the direct costs and, as summary costs were reported, it was unclear which unit costs were included in each category. This does not enable the analysis to be easily reworked for other settings. The quantities of resources used were derived from actual data measured through questionnaires administered to the patients. The costs were derived from official sources. Extensive statistical and sensitivity analyses were performed using the bootstrapping technique. However, the method used to select the ranges used in the sensitivity analysis was not reported. The price year was explicitly reported. Although the study period was 2 years, the costs were not discounted.
Other issues The authors compared their findings with those from other similar studies. They reported that the inter-group and intra-group changes in pain and disability were more distinct in their study. However, differences were not well justified. The issue of generalisability of the results to other settings was not directly addressed. The authors do not appear to have presented their results selectively. The study enrolled employed patients with cLBP and this was reflected in the authors' conclusions. The authors reported only one limitation to their study, the fact that data on resources used were based on retrospective questionnaires administered to the patients, which might have introduced recall-bias into the study.
Implications of the study The authors suggested that encouraging information and advice are major elements for the treatment of patients with cLBP. The discussion highlighted areas where more information could be useful.
Source of funding Sponsored by the Social Insurance Institute of Finland and Finska Lakarsallskapet.
Bibliographic details Niemisto L, Rissanen P, Sarna S, Lahtinen Suopanki T, Lindgren K A, Hurri H. Cost-effectiveness of combined manipulation, stabilizing exercises, and physician consultation compared to physician consultation alone for chronic low back pain: a prospective randomized trial with 2-year follow-up. Spine 2005; 30(10): 1109-1115 Indexing Status Subject indexing assigned by NLM MeSH Adult; Chronic Disease; Combined Modality Therapy; Cost-Benefit Analysis; Disability Evaluation; Exercise Therapy /economics; Female; Humans; Low Back Pain /economics /physiopathology /rehabilitation; Male; Middle Aged; Musculoskeletal Manipulations /economics; Pain Measurement; Patient Education as Topic /economics; Prospective Studies; Quality of Life; Referral and Consultation /economics; Severity of Illness Index; Surveys and Questionnaires; Treatment Outcome AccessionNumber 22006006121 Date bibliographic record published 31/12/2006 Date abstract record published 31/12/2006 |
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