title: Randomized versus historical controls for clinical trials. Secondary Prevention of Low‐Back Pain: A Clinical Trial Effect of Exercise on Sick Leave Due to Low Back Pain: A Randomized, Comparative, Long‐Term Study Lumbar supports and education for the prevention of low back pain in industry: a randomized controlled trial. How study design affects outcomes in comparisons of therapy. I: Medical. Effect of a general fitness program on musculoskeletal symptoms, clinical status, physiological capacity, and perceived work environment among home care service personnel The Delphi list: a criteria list for quality assessment of randomized clinical trials for conducting systematic reviews developed by Delphi consensus. A cost-benefit analysis of a California county's back injury prevention program. Comparison of classroom instruction and independent study in body mechanics. Teaching and Social Support: Effects on Knowledge, Attitudes, and Behaviors to Prevent Low Back Injuries in Industry A controlled trial of an educational program to prevent low back injuries. The secondary prevention of low back pain: a controlled study with follow-up The Influence of Prophylactic Orthoses on Abdominal Strength and Low Back Injury in the Workplace Primary Prevention of Back Symptoms and Absence from Work: A Prospective Randomized Study Among Hospital Employees How study design affects outcomes in comparisons of therapy. II: Surgical. The effects of body mechanics instruction on work performance. Effects of an exercise program on sick leave due to back pain. The effect of body mechanics instruction on work performance among young workers.
abstract: To compare the use of  r and omized controls ( RCTs ) and historical controls ( HCTs )  for clinical trials , we search ed the literature for therapies studied by both methods . We found six therapies for which 50 RCTs and 56 HCTs were reported . Forty-four of 56 HCTs  ( 79 percent ) found the therapy better than the control regimen , but only 10 of 50 RCTs ( 20 percent ) agreed . For each therapy , the treated patients in RCTs and HCTs of the same therapy was largely due to differences in outcome for the control groups , with HCT control patients generally doing worse than the RCT control groups . Adjustment of the outcomes of the HCTs for prognostic factors , when possible , did not appreciably change the results . The data suggest that biases in patient selection may irretrievably weight the outcome of HCts in favor of new therapies . RCTs may miss clinical ly important benefits because of inadequate attention to sample size . The predictive value of each might be improved by reconsidering the use of p less than 0.05 as the significance level for all types of clinical trials , and by the use of confidence intervals around estimates of treatment effects A clinical trial , aim ed at secondary prevention of low-back pain , was performed in 142 hospital employees reporting at least three annual episodes of this condition . Participants were r and omly assigned to one of three groups : a calisthenics program ( CAL ) for 3 months with biweekly sessions of flexion exercises , a back school program ( 5 sessions ) , and a control group . The effectiveness of the two intervention programs was evaluated over a 1-year period . Baseline preintervention data and evaluation at the end of 3 months of intervention and after an additional 6 months were collected . A monthly surveillance for the whole year showed a mean of 4.5 “ painful months ” in the CAL group versus 7.3 and 7.4 months in the back school and control groups , respectively ( P < 0.0001 ) . The superiority of the CAL group was achieved partly because of the significant increase in trunk forward flexion and to initial increment in abdominal muscle strength . The increased trunk flexion was associated with the rate of participation in the CAL sessions . Further research is needed to answer the question of “ intensity versus type of exercise ” by comparing different intervention programs , with similar intensity Study Design . The study was carried out as an open , r and omized , multicenter , parallel‐group study with an observation period of 12 months . Four Norwegian physiotherapy institutes took part . Patients were subsequently followed for 12 months of home exercise on their own , without the supervision of a physiotherapist . Objectives . 1 ) To investigate and compare the effects of two different exercise programs on low back problems in patients after a 1‐year training program under the supervision of a physiotherapist . 2 ) To investigate the effect supervision by , and motivation from , physiotherapists has on training compliance and efficacy . Summary of Background Data . After ordinary physiotherapy treatment for low back problems , patients were r and omly allocated either to a conventional training program design ed by physiotherapists or to a training program using a new Norwegian‐developed training apparatus called the TerapiMaster . The study included 153 patients with low back problems , all of whom had been referred to physiotherapy by their general practitioners . One hundred twenty‐six patients were followed for an additional 12 months when performing home exercise programs on their own . Methods . Monitoring patient satisfaction with the training program , compliance with the program , and absenteeism from work during the training period . Results . Patient satisfaction with both training programs was high , with about 83 % of participating patients completing the study in accordance with the protocol . Mean absenteeism ( SD ) during the preceding year totaled 82.5 days ( 19.8 ) in the conventional training group and 61.6 days ( 14.7 ) in the TerapiMaster group . Significant reductions to 17.2 days ( 6.0 ) and 15.4 days ( 5.3 ) in the two groups , respectively , were recorded during the training period , corresponding to a 75 % to 80 % reduction compared with the preceding 1‐year period . Mean absenteeism showed a further significant decline during the 12‐month period without supervised training . The average values were 9.9 days ( 3.2 ) for conventional training and 9.3 days ( 3.1 ) for the TerapiMaster , respectively . Conclusions . Both exercise programs reduced absenteeism significantly ( 75‐80 % ) . No difference in the effects of the two different programs was discernible . Regular follow‐up through encouragement and variation in the training programs appear to be important factors for motivating patients to adhere to regular exercise programs for low back problems . This thesis was corroborated by the 12‐month study of unsupervised exercise CONTEXT Low back pain is a frequent and costly health problem . Prevention of low back pain is important both for the individual patient and from an economic perspective . OBJECTIVE To assess the efficacy of lumbar supports and education in the prevention of low back pain in industry . DESIGN A r and omized controlled trial with a factorial design . SETTING The cargo department of an airline company in the Netherl and s. PARTICIPANTS A total of 312 workers were r and omized , of whom 282 were available for the 6-month follow-up . INTERVENTIONS Subjects were r and omly assigned to 4 groups : ( 1 ) education ( lifting instructions ) and lumbar support , ( 2 ) education , ( 3 ) lumbar support , and ( 4 ) no intervention . Education consisted of 3 group sessions on lifting techniques with a total duration of 5 hours . Lumbar supports were recommended to be used during working hours for 6 months . MAIN OUTCOME MEASURES Low back pain incidence and sick leave because of back pain during the 6-month intervention period . RESULTS Compliance with wearing the lumbar support at least half the time was 43 % . In the 282 subjects for whom data were available , no statistically significant differences in back pain incidence ( 48 [ 36 % ] of 134 with lumbar support vs 51 [ 34 % ] of 148 without , P=.81 ) or in sick leave because of low back pain ( mean , 0.4 days per month with lumbar support vs 0.4 days without , P=.52 ) were found among the intervention groups . In a subgroup of subjects with low back pain at baseline , lumbar supports reduced the number of days with low back pain per month ( median , 1.2 vs 6.5 days per month ; P=.03 ) . CONCLUSIONS Overall , lumbar supports or education did not lead to a reduction in low back pain incidence or sick leave . The results of the subgroup analysis need to be confirmed by future research . Based on our results , the use of education or lumbar supports can not be recommended in the prevention of low back pain in industry We analysed 113 reports published in 1980 in a sample of medical journals to relate features of study design to the magnitude of gains attributed to new therapies over old . Overall we rated 87 per cent of new therapies as improvements over st and ard therapies . The mean gain ( measured by the Mann-Whitney statistic ) was relatively constant across study design s , except for non-r and omized controlled trials with sequential assignment to therapy , which showed a significantly higher likelihood that a patient would do better on the innovation than on st and ard therapy ( p = 0.004 ) . R and omized controlled trials that did not use a double-blind design had a higher likelihood of showing a gain for the innovation than did double-blind trials ( p = 0.02 ) . Any evaluation of an innovation may include both bias and the true efficacy of the new therapy , therefore we may consider making adjustments for the average bias associated with a study design . When interpreting an evaluation of a new therapy , readers should consider the impact of the following average adjustments to the Mann-Whitney statistic : for trials with non-r and om sequential assignment a decrease of 0.15 , for non-double-blind r and omized controlled trials a decrease of 0.11 The aim of the present controlled study was to evaluate the effect of a general fitness program , performed by an occupational health service , using pre-post assessment for a number of different outcome measures . A total of 160 employees working in the central home care service district of Umeå , Sweden were asked to participate in a program of a 1-year long exercise program . Of the 160 selected , 54 subjects declined to participate and nine subjects were rejected after a medical check up . The remaining 97 subjects participated in a schedule consisting of pre-post medical and physiotherapy examinations , question naires concerning sociodemography , musculoskeletal and general health complaints and work environment , physiological tests of cardiovascular fitness , and of strength and endurance of shoulder flexors and knee extensors , and registration of sick leave . The subjects were r and omly assigned to an exercise ( treatment ) or control group . The exercise group trained twice a week for 1 year using a mixed program including exercises for coordination , strength/endurance , and fitness . The test schedule was repeated for both groups after 1 year . The exercise intervention was associated with positive changes in prevalence and intensity of musculoskeletal and psychosomatic complaints , better physiotherapy status ( less muscle tightness , better neck mobility , and less tender points ) , increased shoulder strength and increased coordination in thigh muscles . However , the exercise group reported worse situations post-exercise concerning aspects of their physical and psychosocial work-environment ( i.e. , concerning ergonomy , influence , appreciation and communication with work manager ) , which might have been due to stress associated with the exercise situation Most systematic review s rely substantially on the assessment of the method ological 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 r and omized 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 question naire , 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 question naires . 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 st and ard for RCTs on many different research topics . This list is not intended to replace , but rather to be used alongside , existing criteria lists Back-related injuries have become a major health problem in the workplace , affecting as many as 35 percent of the work force and accounting for about 25 percent of all compensation cl aims . This study evaluates a back injury prevention program  among employees in a northern California county in 1989 - 90 . Six divisions of the county government were selected for the study because they had the highest prevalence of back pain experienced and the most back-related injuries in recent years . Four of the six divisions were r and omly selected as the intervention group and the remaining two , the  control group . Overall , 77 percent or 205 of the targeted employees in the intervention group participated in the study . The intervention group was given an identical health risk assessment ( HRA ) before and after the 1-year back injury prevention program that offered employees a combination of education , training , physical fitness activities , and ergonomic improvement . The control group was neither given the HRA nor offered the program . The back injury and cost data of both the control and intervention groups were collected before and after the 1-year intervention . The results showed a modest overall decline in back pain prevalence rates , but significant improvement in satisfaction and reduction in risky behaviors . Cost-benefit analysis showed the net benefit of introducing back injury prevention program was $ 161,108 , and the return on investment is 179 percent . Therefore , the study offers suggestive evidence for the initial benefits of a back injury prevention program and lends support to the widely held belief that health promotion in the workplace can reduce employee health risks , increase healthful behaviors and attitudes , and improve attitudes toward the employer organization . Whether such intervention will continue to reap benefits in future years depends , to a large extent , on a favorable work environment and the maintenance and continuation of positive behavioral changes This study was design ed to determine which method of instruction in body mechanics results in the higher subsequent use of the techniques taught . Two groups were formed from nursing personnel at a rural general medical-surgical hospital in the southwestern United States . Subjects from the direct care nursing staff were r and omly assigned to one of the two groups . One group attended two hours of classroom instruction in body mechanics , while the other completed an independent study module . Subjects were pre- and posttested using the Work-Related Body Mechanics Evaluation ( Carlton , 1987 ) while performing a st and ardized lifting task in the clinical setting . Using analysis of covariance , no significant differences were found in the posttest scores of the two groups This study was funded in part by NIH grant AR36308 The authors thank the employees of the United States Postal Service and the American Postal Workers Union ( APWU ) , Boston Metro Area Local , and Maith and lers Local 301 for their help and cooperation ; therapists from the Department of Rehabilitation Services , Bngham and Women 's Hospital for help in training workers ; and Ms Nancy Tanner for BACKGROUND Low back injuries are common and costly , accounting for 15 to 25 percent of injuries covered by workers ' compensation and 30 to 40 percent of the payments made under that program . The high costs of injury , the lack of effective treatment . and the evidence that there are behavioral risk factors have led to widespread use of employee education programs that teach safe lifting and h and ling . The effectiveness of those programs , however , has received little rigorous evaluation . METHODS We evaluated an educational program design ed to prevent low back injury in a r and omized , controlled trial involving about 4000 postal workers . The program , similar to that in wide use in so-called back schools , was taught by experienced physical therapists . Work units of workers and supervisors were trained in a two-session back school ( three hours of training ) , followed by three to four reinforcement sessions over the succeeding few years . Injured subjects ( from both the intervention and the control groups ) were r and omized a second time to receive either training or no training after their return to work . RESULTS Physical therapists trained 2534 postal workers and 134 supervisors . Over 5.5 years of follow-up , 360 workers reported low back injuries , for a rate of 21.2 injuries per 1000 worker-years of risk . The median time off from work per injury was 14 days ( range , 0 to 1717 ) ; the median cost was $ 204 ( range , zero to $ 190,380 ) . After their return to work , 75 workers were injured again . Our comparison of the intervention and control groups found that the education program did not reduce the rate of low back injury , the median cost per injury , the time off from work per injury , the rate of related musculoskeletal injuries , or the rate of repeated injury after return to work ; only the subjects ' knowledge of safe behavior was increased by the training . CONCLUSIONS A large-scale , r and omized , controlled trial of an educational program to prevent work-associated low back injury found no long-term benefits associated with training & NA ; The current investigation studied the effectiveness of a secondary prevention program for nurses with back pain who were deemed at risk for developing a chronic problem . A 2 × 3 repeated measures design was employed with 2 groups and 3 assessment periods . The treatment group received an intervention design ed to reduce current problems , but above all to prevent reinjury and minor pains from becoming chronic medical problems , and it included a physical and behavioral therapy package . The control group was placed on a waiting‐list . Results indicated that the treatment group had significantly greater improvements than the control group for pain intensity , anxiety , sleep quality and fatigue ratings , observed pain behavior , activities , mood , and helplessness . These differences were generally maintained at the 6 month follow‐up . In addition , the treatment group broke a trend for increasing amounts of pain‐related absenteeism , while the control group did not . Taken as a whole , the results suggest that a secondary prevention program aim ed at altering life style factors may represent an effective method for dealing with musculoskeletal pain problems This study was design ed to determine the effect of multimodal intervention and the prevention of back injury , and to evaluate the adverse side effects of using a lumbosacral corset in the workplace . Subjects were 90 male warehouse workers r and omly selected from over 800 employees at a grocery distribution center . Subjects were assigned to three groups : true controls , no back school , no brace orthoses ; back school only ; and back school plus wearing a custom molded lumbosacral orthosis . Comparisons of pre-testing and 6-month follow-up posttesting for abdominal strength , cognitive data , work injury incidence and productivity and use of health care services were evaluated . Controls and training-only group showed no changes in strength productivity or lost time . Orthoses and training-group showed no changes in strength productivity or accident rate ; however , they showed substantially less lost time . This study supports the concept of using education and prophylactic bracing to prevent back injury and reduce time loss . It appears that the use of intermittent prophylactic bracing has no adverse affects on abdominal muscle strength and may contribute to decreased lost time from work injuries The personnel at a geriatric hospital were r and omized into two groups . One group was allowed to exercise during working hours to improve back muscle strength , endurance , and coordination . The other group did not participate in the exercise program and received no further advice or information . After 13 months , the training group had increased back muscle strength . One subject had been absent from work 28 days in the training group whereas 12 subjects had been absent 155 days from work because of low back pain in the control group ( P<0.004 ) . The back pain complaints and intensity of back pain in the training group also decreased in a statistically significant way . Every hour spent by the physiotherapist on the training group reduced the work absence among the participants by 1.3 days , result ing in a cost/benefit ratio greater than 10 We analysed the results of 221 comparisons of an innovation with a st and ard treatment in surgery published in six leading surgery journals in 1983 to relate features of study design to the magnitude of gain . For each comparison we measured the gain attributed to the innovation over the st and ard therapy by the Mann-Whitney statistic and the difference in proportion of treatment successes . For primary treatments ( aim ed at curing or ameliorating a patient 's principal disease ) , an average gain of 0.56 was produced by 20 r and omized controlled trials . This was less than the 0.62 average for four non-r and omized controlled trials , 0.63 for 19 externally controlled trials , and 0.57 for 73 record review s ( 0.50 represents a toss-up between innovation and st and ard ) . For secondary therapies ( used to prevent or treat complications of therapy ) , the average gain was 0.53 for 61 r and omized controlled trials , 0.58 for eleven non-r and omized controlled trials , 0.54 for eight externally controlled trials , and 0.55 for 18 record review s. Readers of studies evaluating new treatments , particularly for primary treatments , may consider adjustment of the gain according to the study type Thirty food service workers were r and omly assigned to two groups ; one group received body mechanics instruction while the other did not . The application of the instruction was measured by evaluating the subjects ' use of body mechanics on a novel lifting and lowering task and during performance on the job . Results indicated that the group which received instruction performed significantly better on the novel task than the group that received no instruction . However , no significant difference between groups was found in performance in the work environment . The role of the occupational therapist in a work-related safety program is also discussed The purpose s of this study were to evaluate the effect of a weekly exercise program on  short-term sick leave ( less than 50 days ) attributable to back pain and to determine whether changes in absenteeism were related to changes in cardiovascular fitness . Subjects were r and omly assigned to an exercise group ( n = 58 ) and a control group ( n = 53 ) .  Sick leave attributable to back pain was determined in the intervention period of 1 1/2 years and a comparable 1 1/2-year period prior to the study . In the exercise group , the number of episodes of back pain and the number of sick-leave days attributable to back pain in the intervention period decreased by over 50 % . Absenteeism attributable to back pain increased in the control group . The decrease in sick leave in the exercise group was not accompanied by any change in cardiovascular fitness . Suggestions for establishing exercise programs are given Thirty young workers ( aged 14 to 19 years ) employed as groundskeepers and custodians were r and omly assigned to two groups ; one group received body mechanics instruction and the other did not . The instruction focused on proper spinal alignment in the work environment . Instruction on  low back pain  began with one classroom session before the subjects ' first day of work and continued during employment with two on-site sessions . The effect of instruction was evaluated through the observation of body mechanics during actual work performance . The results of the study indicate that the group that received instruction performed significantly better than the control group . This paper also discusses the occupational therapist 's role in providing job-specific  body mechanics instruction in the work environment as a primary method of preventing low back pain
target: The trials suggest that work place exercise is effective , braces and education are ineffective , and workplace modification plus education is of unknown value in preventing low back pain
background: A systematic review of r and omised controlled trials was undertaken to evaluate the effectiveness of  workplace interventions  to prevent low back pain .