Biomedical subjects

P G Knipschild

Publications and source records attributed to P G Knipschild.

At least 19 recordsLinked to original sources

PubMed2005

Efficacy of bupropion and nortriptyline for smoking cessation among people at risk for or with chronic obstructive pulmonary disease.

BACKGROUND: The observations that smokers with chronic obstructive pulmonary disease (COPD) are at increased risk of depression and that nicotine may have antidepressant effects and regulate mood provide a rationale for the use of antidepressant drugs for smoking cessation in patients with COPD. No clinical trial has studied the efficacy of bupropion hydrochloride and nortriptyline hydrochloride for smoking cessation in this patient population, to our knowledge. METHODS: In a placebo-controlled double-dummy randomized trial, 255 adults at risk for COPD or with COPD were prescribed sustained-release bupropion (bupropion SR) (150 mg twice daily) or nortriptyline (75 mg once daily) for 12 weeks. All patients received smoking cessation counseling. The main outcome measure was prolonged abstinence from smoking from week 4 to week 26 after the target quit date. RESULTS: The use of bupropion SR and nortriptyline resulted in higher prolonged abstinence rates compared with placebo, although only the difference between bupropion SR and placebo was statistically significant (differences with placebo, 13.1% [95% confidence interval, 1.2%-25.1%] for bupropion SR and 10.2% [95% confidence interval, -1.7% to 22.2%] for nortriptyline). In patients with COPD, bupropion SR and nortriptyline seem efficacious in achieving prolonged abstinence (differences with placebo, 18.9% [95% confidence interval, 3.6%-34.2%] for bupropion SR and 12.9% [95% confidence interval, -0.8% to 26.4%] for nortriptyline). In participants at risk for COPD, no statistically significant differences with placebo in prolonged abstinence rates were found. CONCLUSIONS: Bupropion SR treatment is an efficacious aid to smoking cessation in patients with COPD. Nortriptyline treatment seems to be a useful alternative.

Antidepressive Agents, Second-Generation↗

PubMed2005

The validity and ethics of giving placebo in a randomized nonpharmacologic trial was evaluated.

OBJECTIVE: When studying the effects of a non-pharmacologic intervention, the choice of a control group is often difficult. In a study on the effectiveness of increased water intake on voiding dysfunction in elderly men we used an unusual design. This article addresses the internal validty and ethics of this design. STUDY DESIGN AND SETTING: The randomized trial we evaluated had a 6-month follow-up period and was carried out among 141 elderly men with moderate lower urinary tract symptoms. The experimental group was given the instruction to drink more water, the control group received placebo medication. The participants were not informed that there was a 50% chance of receiving placebo. We measured whether the prior expectations and preferences were comparable for the two study groups, whether blinding was preserved throughout the study period, and whether the participants considered this design ethical. RESULTS: Prior to randomization, patients had higher expectations for the experimental intervention, but there was not statistically significant difference in their preference. During the study period, two out of 71 patients in the control group unmasked the placebo. In general, both groups fully agreed with the informed consent procedure. CONCLUSION: This design can be considered when the effects of a non-pharmacologic interventions are studied.

Aged↗

PubMed2005

Increasing the daily water intake for the prophylactic treatment of headache: a pilot trial.

Dehydration is commonly believed to result in headache, but the effectiveness of increasing the water intake in patients who frequently suffer from headaches has not been studied thus far. In a pilot study, we examined the possible effects and feasibility of increased water intake in headache patients. Eighteen headache patients (all had migraine, two also had tension-type headache) were randomly allocated to placebo medication, or the advice to additionally drink 1.5 l of water per day, for a period of 12 weeks. Effect measurements consisted of a 2 weeks headache diary and the Migraine Specific Quality of Life (MSQOL) questionnaire. The advice to increase the daily fluid intake by 1.5 l increased the fluid intake in the intervention group by approximately 1 l. This reduced the total hours of headache in 2 weeks by 21 h (95% CI: -48 to 5). Mean headache intensity decreased by 13 mm (95% CI: -32 to 5) on a visual analogue scale (VAS). The effects on MSQOL, number of headache episodes, and medication seemed to be small. The data of the present study suggest a reduction in the total number of hours and intensity of headache episodes after increased water intake. Our results seem to justify larger scaled research on the effectiveness of increased water intake in headache patients.

Confidence Intervals↗

PubMed2000

[Roaming through methodology. XXIII. The need for randomization and blinding in therapeutic investigations].

After the start of a treatment patients often get better. This may be due to the treatment or other circumstances. There may be errors in the execution of the study, the disease may disappear spontaneously, effective co-interventions may be present and possibly there are also placebo effects. Most of the time, only sufficiently large randomised, blinded research is useful to estimate the efficacy of drugs and of other treatments. The best comparison is often between the new treatment and the best available one, not the sham treatment.

Double-Blind Method↗

PubMed2000

Balneotherapy for rheumatoid arthritis and osteoarthritis.

BACKGROUND: Balneotherapy (hydrotherapy or spa therapy) for patients with arthritis is one of the oldest forms of therapy. One of the aims of balneotherapy is to soothe the pain and as a consequence to relieve patients' suffering and make them feel well. OBJECTIVES: To perform a systematic review to assess the effects of balneotherapy for rheumatoid arthritis and osteoarthritis. SEARCH STRATEGY: Using the Cochrane search strategy, studies were found by screening: 1) The Medline CD-ROM database from 1966 to June 1999 and 2) the database from the Cochrane Field 'Rehabilitation and Related Therapies', which contains also studies published in journals not covered by Medline. Also, 3) reference checking and 4) personal communications with authors was carried out to retrieve eligible studies. To perform an adequate assessment of the methodological quality the languages of the publications had to be: Dutch, English, French or German. Date of the most recent literature search: June, 1999 SELECTION CRITERIA: Studies were eligible if they were randomized controlled trials (RCT) comparing balneotherapy with any intervention or with no intervention. Patients included had rheumatoid arthritis (RA), osteoarthritis (OA) or some other form of arthritis. Trials incorporating patients with definite or classical rheumatoid arthritis (RA) as defined by the American Rheumatism Association Criteria (ARA) (Ropes 1958) (these criteria have changed over time) or by the criteria of Steinbrocker (1949) were regarded as a separate group. At least one of the WHO/ILAR core set of endpoints for RA clinical trials had to be the main outcome measures. DATA COLLECTION AND ANALYSIS: A criteria list used to assess the methodological quality was the one developed at the Department of Epidemiology at the Maastricht University, called "the Maastricht list". The quality scores and data abstraction of the studies were carried out independently by two reviewers (HdV, RdB). Disagreements were solved by consensus. MAIN RESULTS: Ten trials with 607 patients were included in this review. Most trials reported positive findings, but were methodologically flawed to some extent. A 'quality of life' outcome was reported by two trials. Just one of the randomized trials mentioned an intention-to-treat analysis and only three performed a comparison of effects between groups. Pooling of the data was not performed, because of heterogeneity of the studies, multiple outcome measurements, and, apart from two studies, the overall data presentation was too scarce to enable pooling of the data. REVIEWER'S CONCLUSIONS: One cannot ignore the positive findings reported in most trials. However the scientific evidence is weak because of the poor methodological quality, the absence of an adequate statistical analysis, and the absence, for the patient, of most essential outcome measures (pain, quality of life), Therefore, the noted "positive findings" should be viewed with caution. Because of the methodological flaws an answer about the efficacy of balneotherapy cannot be provided at this time. Flaws found in the reviewed studies could be avoided in future trials.

Arthritis, Rheumatoid↗

PubMed2000

Randomized clinical trial on the use of antispasmodic drugs in barium enema: impact on radiological practice.

PURPOSE: To assess the willingness of radiologists to change their practice when the results of a randomized clinical trial (RCT) on the use of antispasmodic drugs in barium enema are presented. MATERIALS AND METHODS: During the years 1994 and 1995 two postal questionnaires were sent to 481 practicing radiologists who were all members of the Netherlands Society of Radiology. In the first questionnaire the respondents were asked to give the characteristics of their practices in performing daily barium enema. The data from this questionnaire was used as a reference. The second questionnaire was sent to the respondents together with an abstract on the randomized clinical trial supporting the use of antispasmodic drugs in barium enema. We also indicated a preference for Buscopan over Glucagon as the antispasmodic drug. The willingness to change prescription habits was measured by comparing the data of the two questionnaires. RESULTS: Of 481 practicing radiologists, 312 responded to the first questionnaire and gave information of their prescription habits (response rate 64%). These 312 responders were sent an abstract of the RCT and were asked to fill out a second questionnaire to determine their willingness to change their practice. Two hundred and sixty-seven radiologists responded (response rate 86%). A significant number of 119 (51%) were willing to increase the use of antispasmodic drugs. A significant number of 128 (55%) chose to increase the use of Buscopan, while a significant number of 81 (32%) were willing to decrease the use of Glucagon. CONCLUSION: Direct exposure to the results of an RCT recommending the use of antispasmodic drugs in barium enema, especially Buscopan, is likely to increase its use by practicing radiologists.

Attitude of Health Personnel↗

PubMed2000

The efficacy of ginkgo for elderly people with dementia and age-associated memory impairment: new results of a randomized clinical trial.

OBJECTIVES: To evaluate the efficacy, the dose-dependence, and the durability of the effect of the ginkgo biloba special extract EGb 761 (ginkgo) in older people with dementia or age-associated memory impairment. DESIGN: A 24-week, randomized, double-blind, placebo-controlled, parallel-group, multicenter trial. SETTING: Homes for the elderly in the southern part of the Netherlands. PARTICIPANTS: Older persons with dementia (either Alzheimer's dementia or vascular dementia; mild to moderate degree) or age-associated memory impairment (AAMI). 214 Participants were recruited from 39 homes for the elderly. INTERVENTION: The participants were allocated randomly to treatment with EGb 761 (2 tablets per day, total dosage either 240 (high dose) or 160 (usual dose) mg/day) or placebo (0 mg/d). The total intervention period was 24 weeks. After 12 weeks of treatment, the initial ginkgo users were randomized once again to either continued ginkgo treatment or placebo treatment. Initial placebo use was prolonged after 12 weeks. MEASUREMENTS: Outcomes were assessed after 12 and 24 weeks of intervention. Outcome measures included neuropsychological testing (trail-making speed (NAI-ZVT-G), digit memory span (NAI-ZN-G), and verbal learning (NAI-WL)), clinical assessment (presence and severity of geriatric symptoms (SCAG), depressive mood (GDS), self-perceived health and memory status (report marks)), and behavioral assessment (self-reported level of instrumental daily life activities). RESULTS: An intention-to-treat analysis showed no effect on each of the outcome measures for participants who were assigned to ginkgo (n = 79) compared with placebo (n = 44) for the entire 24-week period. After 12 weeks of treatment, the combined high dose and usual dose ginkgo groups (n = 166) performed slightly better with regard to self-reported activities of daily life but slightly worse with regard to self-perceived health status compared with the placebo group (n = 48). No beneficial effects of a higher dose or a prolonged duration of ginkgo treatment were found. We could not detect any subgroup that benefited from ginkgo. Ginkgo use was also not associated with the occurrence of (serious) adverse events. CONCLUSIONS: The results of our trial suggest that ginkgo is not effective as a treatment for older people with mild to moderate dementia or age-associated memory impairment. Our results contrast sharply with those of previous ginkgo trials.

Activities of Daily Living↗

PubMed1999

No effect of bipolar interferential electrotherapy and pulsed ultrasound for soft tissue shoulder disorders: a randomised controlled trial.

OBJECTIVE: To assess the efficacy of bipolar interferential electrotherapy (ET) and pulsed ultrasound (US) as adjuvants to exercise therapy for soft tissue shoulder disorders (SD). METHODS: Randomised placebo controlled trial with a two by two factorial design plus an additional control group in 17 primary care physiotherapy practices in the south of the Netherlands. Patients with shoulder pain and/or restricted shoulder mobility, because of a soft tissue impairment without underlying specific or generalised condition, were enrolled if they had not recovered after six sessions of exercise therapy in two weeks. They were randomised to receive (1) active ET plus active US; (2) active ET plus dummy US; (3) dummy ET plus active US; (4) dummy ET plus dummy US; or (5) no adjuvants. Additionally, they received a maximum of 12 sessions of exercise therapy in six weeks. Measurements at baseline, 6 weeks and 3, 6, 9, and 12 months later were blinded for treatment. OUTCOME MEASURES: recovery, functional status, chief complaint, pain, clinical status, and range of motion. RESULTS: After written informed consent 180 patients were randomised: both the active treatments were given to 73 patients, both the dummy treatments to 72 patients, and 35 patients received no adjuvants. Prognosis of groups appeared similar at baseline. Blinding was successfully maintained. At six weeks seven patients (20%) without adjuvants reported very large improvement (including complete recovery), 17 (23%) and 16 (22%) with active and dummy ET, and 19 (26%) and 14 (19%) with active and dummy US. These proportions increased to about 40% at three months, but remained virtually stable thereafter. Up to 12 months follow up the 95% CI for differences between groups for all outcomes include zero. CONCLUSION: Neither ET nor US prove to be effective as adjuvants to exercise therapy for soft tissue SD.

Adult↗

PubMed1998

Low-level laser therapy in ankle sprains: a randomized clinical trial.

OBJECTIVE: To test the efficacy of low-level laser therapy on lateral ankle sprains as an addition to a standardized treatment regimen, a trial was conducted in which high-dose laser (5J/cm2), low-dose laser (0.5J/cm2), and placebo laser therapy (0J/cm2) at skin level were compared. DESIGN: Randomized, double-blind, controlled clinical trial with a follow-up of 1 year. Patients, therapists, assessors, and analysts were blinded to the assigned treatment. SETTING: An ambulatory care setting. PATIENTS: After informed consent and verification of exclusion criteria, 217 patients with acute lateral ankle sprains were randomized to three groups from September 1, 1993, through December 31, 1995. INTERVENTIONS: Twelve treatments of 904nm laser therapy in 4 weeks as an adjunct to a standardized treatment regimen of 4 weeks of brace therapy combined with standardized home exercises and advice. The laser therapy device used was a 904nm Ga-As laser, with 25-watt peak power and 5,000 or 500Hz frequency, a pulse duration of 200nsec, and an irradiated area of 1cm2. PRIMARY OUTCOME MEASURES: Pain and function as reported by the patient. RESULTS: Intention-to-treat analysis of the short-term results showed no statistically significant difference on the primary outcome measure, pain (p = .41), although the placebo group showed slightly less pain. Function was significantly better in the placebo group at 10 days (p = .01) and 14 days (p = .03) after randomization. The placebo group also performed significantly better on days of sick leave (p = .02) and at some points for hindrance in activities in daily life and pressure pain, as well as subjective recovery (p = .05). Intention-to-treat analysis showed that total days of absenteeism from work and sports were remarkably lower in the placebo group than in the laser groups, ranging from 3.7 to 5.3 and 6 to 8 days, respectively. The total number of relapses at 1 year in the low-dose laser group (n = 22) was significantly higher (p = .04) than in the other two groups (high laser, n = 13; placebo, n = 13). Subgroup analysis to correct for possible confounders did not alter these findings. CONCLUSIONS: Neither high- nor low-dose laser therapy is effective in the treatment of lateral ankle sprains.

Adult↗

PubMed1998

Balneotherapy and quality assessment: interobserver reliability of the Maastricht criteria list and the need for blinded quality assessment.

This study investigates aspects of the reliability of the Maastricht criteria list for quality assessment in systematic reviews, and whether blinded reviewing is necessary to prevent review bias. We used the data set of 12 articles from a systematic review concerning the efficacy of balneotherapy in patients with arthritis. Twenty reviewers participated of which two reviewers, who have been involved in developing the Maastricht criteria list, acted as reference standard. Half of all assessments were performed blindly. A high level of agreement was found between the reviewers and a high level of correlation with the reference standard. The quality scores between the blinded and unblinded assessment did not differ much. Based on the results we conclude that the Maastricht criteria list is a reliable instrument in quality assessment of clinical trials. Within the limits of this study we found no evidence that blinding is necessary to prevent review bias.

Arthritis↗

PubMed1998

The Delphi list: a criteria list for quality assessment of randomized clinical trials for conducting systematic reviews developed by Delphi consensus.

Most systematic reviews rely substantially on the assessment of the methodological quality of the individual trials. The aim of this study was to obtain consensus among experts about a set of generic core items for quality assessment of randomized clinical trials (RCTs). The invited participants were experts in the field of quality assessment of RCTs. The initial item pool contained all items from existing criteria lists. Subsequently, we reduced the number of items by using the Delphi consensus technique. Each Delphi round comprised a questionnaire, an analysis, and a feedback report. The feedback report included staff team decisions made on the basis of the analysis and their justification. A total of 33 international experts agreed to participate, of whom 21 completed all questionnaires. The initial item pool of 206 items was reduced to 9 items in three Delphi rounds. The final criteria list (the Delphi list) was satisfactory to all participants. It is a starting point on the way to a minimum reference standard for RCTs on many different research topics. This list is not intended to replace, but rather to be used alongside, existing criteria lists.

Delphi Technique↗

PubMed1998

Optimization of placebos for double-blind clinical trials. Experience with a phytopharmaceutical.

The maintenance of double-blind conditions in placebo-controlled trials depends on the quality of the placebo preparation. The placebo should match the active substance-containing preparation as closely as possible, but it must not contain any substances that might themselves be pharmacologically active. Active substances characterized by a particular colour, taste, smell or other easily perceptible properties constitute a challenge to researchers. The way of developing a placebo that matches a phytopharmaceutical to a satisfactory extent is described and discussed.

Aged↗

PubMed1997

Efficacy of traction for nonspecific low back pain. 12-week and 6-month results of a randomized clinical trial.

STUDY DESIGN: A randomized clinical trial. OBJECTIVES: To assess the efficacy of motorized continuous traction for low back pain. SUMMARY OF BACKGROUND DATA: The available studies on the efficacy of lumbar traction do not allow clear conclusions because of severe methodologic flaws. The current trial aimed to overcome these shortcomings. METHODS: Patients with at least 6 weeks of nonspecific low back pain were selected. High-dose traction was compared with sham (or low-dose) traction. Sham traction was given with a specially developed brace that becomes tighter in the back during traction. This was experienced as if real traction were exerted. The patients and the outcome assessor were unaware of treatment allocation. Outcome measures were: patient's global perceived effect, severity of main complaints, functional status, pain, range of motion, work absence, and medical treatment. Results for the outcome measures at 12 weeks and 6 months after randomization are presented. RESULTS: One hundred and fifty-one patients were randomly allocated to one of the two treatment methods. Intention-to-treat analysis of the 12-week and 6-month results showed no statistically significant differences between the groups on all outcome measures: all 95% confidence intervals included the value zero. The number of patients lost to follow-up study was very low. Other analyses showed the same results. CONCLUSIONS: Most common flaws of earlier studies on traction therapy could be overcome. This trial did not support the claim that traction is efficacious for patients with low back pain.

Adult↗

PubMed1997

Reliability of lumbar spine radiograph reading by chiropractors.

STUDY DESIGN: An intraobserver and interobserver study on the reproducibility of data was performed. OBJECTIVES: This study investigates the variability in the interpretation of lumbar spine radiographs by chiropractors working in private practice. SUMMARY OF BACKGROUND DATA: In chiropractic practice radiographs are used often, but this use is currently under debate. Therefore, there is a need for further study of the value of diagnoses made by radiographs by chiropractors. An acceptable intra- and interobserver agreement in radiograph reading is a prerequisite for a useful application of radiographs as a diagnostic tool in daily practice and in research. METHODS: Four chiropractors read 100 blinded sets of standard, erect anteroposterior and lateral lumbar radiographs independently. The same set was read in two separate sessions with a 2-month interval. The first session revealed the interobserver agreement. The comparison of the ratings by the same assessor in the two sessions indicated the intraobserver agreement. The assessors used a specially developed criteria list with emphasis on "nonspecific" radiographic findings. The prevalence of some important categories was increased artificially. Agreement was expressed in percentage agreement and generalized kappa, combining the results of all four assessors. RESULTS: Most kappas ranged from 0.40 to 0.75, representing fair to good agreement. In general, intraobserver agreement was better than interobserver agreement. The low kappas that were found may be explained partially by the high-agreement-low-kappa paradox as a result of a low prevalence. CONCLUSION: The kappas and percentage agreement were acceptable, although not excellent. These results will be beneficial for future research on the value of radiograph diagnosis of nonspecific findings for delivery of safe and effective chiropractic therapy.

Adult↗

PubMed1997

The prognosis of ankle sprains.

We developed a new diagnostic tool for predicting the severity of ankle sprains just after injury. Since hard data obtained by diagnostic imaging techniques are still imperfect, we decided to use data from individual medical history and signs and symptoms that are part of the admission routine. During a three month-period data were collected on thirty-five patients with lateral ankle sprains who visited the first aid department of the University Hospital of Maastricht. Assessments took place at admission and at two and four weeks after injury. Assessors were the first-aid physician, a physiotherapist and the patient. Dependent variables were healed ankle in two and four weeks. Predicting variables were the data obtained at admission by the physician, the physiotherapist and the patient. The ability to predict outcome after two and four weeks was determined in a bivariate analysis, followed by logistic modelling. Accurate prediction of recovery time at admission appeared to be possible. Best two weeks predictor was the modified function score, an accuracy of 97% was achieved. Four weeks prediction was most accurate when function score was used together with the report mark from the doctor and the palpation score (accuracy of 81%).

Activities of Daily Living↗

PubMed1997

Taking baths: the efficacy of balneotherapy in patients with arthritis. A systematic review.

OBJECTIVE: To review English, French, German, and Dutch language studies of the effectiveness of balneotherapy. Balneotherapy (hydrotherapy or spa therapy) is one of the oldest forms of therapy for patients with arthritis. One of the aims of balneotherapy is to relieve pain. METHODS: We performed a systematic review that included randomized and nonrandomized studies. Quality scores of the studies were determined using a criteria list. RESULTS: Most studies report positive findings, but all studies showed methodological flaws. A quality of life measurement was never reported as an outcome measure. None of the randomized clinical trials included intention-to-treat analysis or comparison of effects between groups. CONCLUSION: Because of the methodological flaws a conclusion about the efficacy of balneotherapy cannot be provided from studies we reviewed. We conclude that most flaws found could be avoidable in future research.

Arthritis↗

PubMed1996

Complications of spinal manipulation: a comprehensive review of the literature.

BACKGROUND: Spinal manipulative therapy (SMT) is a frequently applied therapy for back and neck pain. Serious complications of SMT are presented primarily in case reports. Many patients seen by physicians also seek care from therapists applying manipulative techniques. Therefore, background information on the risks of SMT is essential for physicians. METHODS: Relevant case reports, surveys, and review articles were identified using a comprehensive search of online and bibliographical databases. For every case, a record was made of first author, publication year, country, age and sex of the patient, background of the manipulator, preexisting conditions, type of complication, and course of the complication. Based on case reports and surveys, an estimation was made of the risk for the most frequently reported complications: vertebrobasilar accidents (VBAs) and cauda equina syndrome (CES). RESULTS: We derived 295 complications of spinal manipulations from the literature: 165 VBAs; 61 cases with disc herniation or progression to CES; 13 cerebral complications other than VBAs; and 56 other types of complications. The average age of patients with VBA was 38 years. Vertebrobasilar accidents occur mainly after a cervical manipulation with a rotatory component. Estimates of VBA range from 1 per 20,000 patients to 1 per 1 million cervical manipulations. The incidence of CES is estimated to be less that 1 per 1 million treatments. CONCLUSIONS: It is difficult to estimate the incidence of SMT complications, as they are probably underreported in the literature. Most non-VBA complications can be prevented by excluding patients with contraindications for SMT. Patients who develop complications such as CES should be treated as soon as possible. VBAs, however, are difficult to prevent and treat. Referral for SMT should not be made to practitioners applying rotatory cervical manipulation. Information about the risk of VBA should be included in an informed consent procedure for cervical manipulation with thrust techniques.

Back Pain↗

PubMed1995

The relationship between methodological quality and conclusions in reviews of spinal manipulation.

OBJECTIVE: To study the relationship between the methodological quality and other characteristics of reviews of spinal manipulation for low back pain on the one hand and the reviewers' conclusions on the effectiveness of manipulation on the other hand. DATA SOURCES: Reviews identified by MEDLINE search, citation tracking, library search, and correspondence with experts. STUDY SELECTION: English- or Dutch-language reviews published up to 1993 dealing with spinal manipulation for low back pain that include at least two randomized clinical trials (RCTs). DATA EXTRACTION: Methodological quality was assessed using a standardized criteria list applied independently by two assessors (range, 0% to 100%). Other extracted characteristics were the comprehensiveness of the search, selective citation of studies, language, inclusion of non-RCTs, type of publication, reviewers' professional backgrounds, and publication in a spinal manipulation journal or book. The reviewers' conclusions were classified as negative, neutral, or positive. DATA SYNTHESIS: A total of 51 reviews were assessed, 17 of which were neutral and 34 positive. The methodological quality was low, with a median score of 23%. Nine of the 10 methodologically best reviews were positive. Other factors associated with a positive reviewers' conclusion were review of spinal manipulation only, inclusion of a spinal manipulator in the review team, and a comprehensive literature search. CONCLUSIONS: The majority of the reviews concluded that spinal manipulation is an effective treatment for low back pain. Although, in particular, the reviews with a relatively high methodological quality had a positive conclusion, strong conclusions were precluded by the overall low quality of the reviews. More empirical research on the review methods applied to other therapies in other professional fields is needed to further explore our findings about the factors related to a positive reviewers' conclusion.

Humans↗