Development of a critical appraisal tool for models predicting the impact of 'test, trace, and protect' programmes on COVID-19 transmission

OBJECTIVES

To develop a critical appraisal tool for non-computational-specialist public health professionals to assess the quality and relevance of modelling studies about Test and Trace (and Protect - TTP) programmes' impact on COVID-19 transmission.

STUDY DESIGN

Decision-making tool development.

METHODS

Using Tugwell et al.'s 1985 Health Care Effectiveness equation as a conceptual framework, combined with a purposive search of the relevant early modeling literature, we developed six critical appraisal questions for the rapid assessment of modeling studies related to the evaluation of TTP programmes' effectiveness.

RESULTS

By applying the critical appraisal tool to selected recent COVID-19 modeling studies, we demonstrate how models can be evaluated using the six questions to evaluate internal and external validity and relevance.

CONCLUSIONS

These six critical appraisal questions are able to discriminate between modeling studies of higher and lower quality and relevance to evaluating TTP programmes' impact. However, these questions require independent validation in a larger and systematic sample of relevant modeling studies which have appeared in later stages of the pandemic.

Bridging the academic and practice/policy gap in public health: perspectives from Scotland and Canada

This article presents a critical commentary of specific organizational models and practices for bridging 'the gap' between public health research and policy and practice. The authors draw on personal experiences of such models in addition to the wider knowledge translation and exchange literature to reflect on their strengths and weaknesses as implemented in Scotland and Canada since the early 1990s.

Fermentation products as feed additives mitigate some ill-effects of heat stress in pigs

Heat stress (HS) may result in economic losses to pig producers across the USA and worldwide. Despite significant advancements in management practices, HS continues to be a challenge. In this study, an in-feed antibiotic (carbadox, CBX) and antibiotic alternatives ( [XPC], and [SGX] fermentation products) were evaluated in a standard pig starter diet as mitigations against the negative effects of HS in pigs. A total of 100 gilts were obtained at weaning (6.87 ± 0.82 kg BW, 19.36 ± 0.72 d of age) and randomly assigned to dietary treatments (2 rooms/treatment, 2 pens/room, 6 to 7 pigs/pen). After 4 wk of dietary acclimation, half of the pigs in each dietary group (1 room/dietary treatment) were exposed to repeated heat stress conditions (RHS; daily cycles of 19 h at 25°C and 5 h at 40°C, repeated for 9 d), and the remaining pigs were housed at constant thermal neutral temperature (25°C, [NHS]). Pigs subjected to RHS had elevated skin surface temperature ( < 0.05; average 41.7°C) and respiration rate ( < 0.05; 199 breaths per minute (bpm) during HS, and overall reduced ( < 0.05) BW, ADG, ADFI, and G:F regardless of dietary treatment. Independent of diet, RHS pigs had significantly shorter ( < 0.05) jejunum villi on d 3 and d 9 compared to NHS pigs. Heat stress resulted in decreased villus height to crypt depth ratio (V:C) in pigs fed with control diet with no added feed additive (NON) and CBX diets at d 3, whereas the pigs fed diets containing XPC or SGX showed no decrease. Transcriptional expression of genes involved in cellular stress (, , , ), tight junction integrity (, , ), and immune response (, , and ) were measured in the ileum mucosa. Pigs in all dietary treatments subjected to RHS had significantly higher ( < 0.05) transcript levels of and , and an upward trend ( < 0.07) of mRNA expression. RHS pigs had higher ( < 0.05) transcript levels of and in NON diet, in XPC and CBX diets, and in SGX diet compared to the respective diet-matched pigs in the NHS conditions. Neither RHS nor diet affected peripheral natural killer () cell numbers or NK cell lytic activity. In conclusion, pigs subjected to RHS had decreased performance, and supplementation with fermentation products in the feed (XPC and SGX) protected pigs from injury to the jejunum mucosa.

Influence of dietary -arginine supplementation of sows during late pregnancy on piglet birth weight and sow and litter performance during lactation

Two experiments were conducted to determine the effect of feeding supplemental -Arg during late pregnancy on piglet birth weight and preweaning performance. In Exp. 1, 97 gilts and sows were allotted (gestation d 93) to receive a control diet (CON; 19.8 g standardized ileal digestible [SID] Arg/d) or the CON + 1.0% -Arg (ARG; 46.6 g SID Arg/d). Gilts and sows were weighed on gestation d 93 and 110, 48 h after farrowing, and at weaning. Data, including number born alive, number weaned, individual birth and weaning weight, and placenta weight, were recorded. Blood samples were collected on d 93 and 110 and analyzed for plasma IGF-1, insulin, and blood urea nitrogen concentration. In a second experiment, 383 sows in a commercial research farm were allotted to receive CON or ARG. An -Arg premix was provided daily by top dress beginning at gestation d 81 (±0.1 d) and fed for an average of 35 d (±0.2 d). Sows received 2.73 kg feed/d with CON sows provided 17 g SID Arg/d and ARG sows receiving a total of 44 g SID Arg/d. Litter birth weight was recorded and average birth weight was computed. In a subset of 82 sows, individual birth weights were recorded. In Exp. 1, there was a tendency for greater late pregnancy maternal BW gain ( = 0.06) in ARG compared with CON. A tendency for a parity × treatment interaction was observed for late pregnancy BW gain, with first litter sows fed ARG gaining the most, gilts fed ARG intermediate, and all other treatments gaining the least ( = 0.10). No differences between treatment groups were observed for maternal plasma IGF-1, insulin, and urea nitrogen and in progeny performance to weaning ( > 0.28). In Exp. 2, piglet birth weight was more effectively tested because of the large number of multiparous sows involved. There was a tendency for individual birth weight to decline in ARG compared with CON ( < 0.08), but birth weight distribution between <0.80 and >2.8 kg was similar. No other differences were observed ( > 0.18). In conclusion, late pregnancy supplementation with -Arg had no effect on number of pigs born alive, piglet birth weight, or lactation performance.

Young people's exposure to point-of-sale tobacco products and promotions

OBJECTIVES

Point of sale (POS) displays are one of the most important forms of tobacco marketing still permitted in many countries. Reliable methods for measuring exposure to such displays are needed in order to assess their potential impact, particularly on smoking attitudes and uptake among young people. In this study we use a novel method for evaluating POS exposure based on young people's use of retail outlets and recall of tobacco displays and observational data on the characteristics of displays.

STUDY DESIGN

Observational audit of retail outlets (n = 96) and school-based pupil survey (n = 1482) in four Scottish communities reflecting different levels of social deprivation and urbanisation, conducted in 2013 before legislation to remove POS displays was implemented in supermarkets.

METHODS

Measures were taken of: visibility and placement of tobacco displays; internal and external advertising; display unit size, branding and design; visibility of pack warnings; proximity of tobacco products to products of potential interest to children and young people; pupils' self-reported frequency of visiting retail outlets; and pupils' recall of tobacco displays. Variation in POS exposure across social and demographic groups was assessed.

RESULTS

Displays were highly visible within outlets and, in over half the stores, from the public footway outside. Tobacco products were displayed in close proximity to products of interest to children (e.g. confectionery, in 70% of stores). Eighty percent of pupils recalled seeing tobacco displays, with those from deprived areas more likely to recall displays in small shops. When confectioners, tobacconists and newsagents (CTNs) and grocery/convenience stores (two of the outlet types most often visited by young people) were examined separately, average tobacco display unit sizes were significantly larger in those outlets in more deprived areas.

CONCLUSIONS

POS displays remain a key vector in most countries for advertising tobacco products, and it is important to develop robust measures of exposure. The data reported in this paper provide a baseline measure for evaluating the efficacy of legislation prohibiting such displays.

Immigrants' duration of residence and adverse birth outcomes: a population-based study

OBJECTIVE

This study aimed to examine preterm and small-for-gestational-age (SGA) births among immigrants, by duration of residence, and to compare them with the Canadian-born population.

DESIGN

Population-based cross-sectional study with retrospective assessment of immigration.

SETTING

Metropolitan areas of Ontario, Canada.

POPULATION

A total of 83 233 singleton newborns born to immigrant mothers and 314 237 newborns born to non-immigrant mothers.

METHODS

We linked a database of immigrants acquiring permanent residence in Ontario, Canada, in the period 1985-2000 with mother-infant hospital records (2002-2007). Duration of residence was measured as completed years from arrival to Canada to delivery/birth. Logistic regression models were used to estimate the effects of duration of residence with adjusted odds ratios and 95% confidence intervals. In analyses restricted to immigrants only, hierarchical models were used to account for the clustering of births into maternal countries of birth.

MAIN OUTCOME MEASURES

Preterm birth (PTB) and SGA birth.

RESULTS

Recent immigrants (<5 years) had a lower risk of PTB (4.7%) than non-immigrants (6.2%), but those with > or =15 years of stay were at higher risk (7.4%). Among immigrants, a 5-year increase in Canadian residence was associated with an increase in PTB (AOR 1.14, 95% CI 1.10-1.19), but not in SGA birth (AOR 0.99, 95% CI 0.96-1.02).

CONCLUSIONS

Time since migration was associated with increases in the risk of PTB, but was not associated with an increase in SGA births. Ignoring duration of residence may mask important disparities in preterm delivery between immigrants and non-immigrants, and between immigrant subgroups categorised by their duration of residence.

Carcinoma of the breast wire localisation post nuclear medicine sentinel lymph node imaging. Are radiologists receiving a significant dose?

OBJECTIVE

To assess the radiation dose received by the radiologist when performing wire localisation for axillary radio-isotope sentinel node imaging-guided biopsy in patients with impalpable breast cancers treated with breast-preserving excision. When wire placement follows radio-isotope sentinel node imaging (RSNI) the radiologist is exposed to a radiation risk that has never been previously assessed.

METHODS

Radiation doses to radiologists performing ultrasound-guided localisation following nuclear medicine sentinel node imaging were measured for procedures on the day of surgery (20 MBq) and also on the day before surgery (40 MBq). These measurements were compared with theoretically calculated doses.

RESULTS

Twelve patients showed comparable results between measurements and estimated doses. The mean measured dose was 1.8 muSv (estimated 1.8 muSv) for same-day and 4.8 muSv (estimated 3.4 muSv) for next-day surgery cases. At worst, radiologists who perform 36 wire localisations per year immediately following RSNI receive a radiation dose of 0.17 mSv.

CONCLUSIONS

This study highlights the need to inform radiologists of the relative risk when performing pre-surgical localisation after RSNI. This risk should be justified locally in accordance with the total dose received by the localising radiologist. Particular consideration should be given to pregnant staff and the possibility of performing wire localisations before radio-isotope injection.

Examining the relationships between job control and health status: a path analysis approach

OBJECTIVE

To examine the pathways through which job control affects health status; to examine if the effects of job control on health status are attenuated by including other measures associated with lower socioeconomic status, and to examine if the relationship between job control and health status is consistent across socioeconomic status groups.

DESIGN

A prospective observational cohort study over eight years (1994-2002).

PARTICIPANTS

4886 Respondents aged 25-60 years, who were non-self-employed labour force participants, working more than 20 hours per week, without physical or mental limitations restricting the type or amount of work they could do at baseline. After longitudinal attrition, the remaining study sample was 3411 (87% of the original study sample who did not die or become pregnant during the survey period).

MAIN RESULTS

Low job control in 1994 was associated with worse than expected self-rated health in 2002, both directly and indirectly via a lower physical activity level in 1996. Adjustment for other factors associated with low socioeconomic status did not attenuate these relationships to a large extent. No differences were found in the effects of job control on physical activity or health status between socioeconomic groups (high and low education and high and low household income).

CONCLUSIONS

The inclusion of other factors associated with lower socioeconomic status did not attenuate the direct and indirect effects of job control on health status. The finding that low job control is associated with lower physical activity levels deserves further investigation, given the increasing concern about rising levels of obesity in the developed world.

Training of staff for the delivery of PET/CT services in the UK

Evidence for the cost effectiveness of PET/CT imaging is now driving the widespread introduction of PET/CT services throughout the UK. The provision of PET/CT facilities will require a workforce of medical, scientific, technical and engineering staff who are adequately trained and fit for purpose. Suitably trained staff in this speciality are scarce. The development and accreditation of training courses and other educational resources for training programmes in all disciplines will therefore be required at a national and regional level. The implementation of PET/CT training can be achieved more cost-effectively by developing multi-professional learning resources whenever possible. It is intended that the recommendations would be implemented by close co-operation of both public and private healthcare providers together with educational establishments.

Childhood and early adult predictors of risk of incident back pain: Ontario Child Health Study 2001 follow-up

Musculoskeletal disorders of the back and spine are a leading cause of disability in working-age populations. There is limited information on the potential consequences of childhood socioeconomic and health status on the risk of incident back pain in early adulthood. The authors describe factors associated with having had a first episode of back pain during the past year in the Ontario Child Health Study, a prospective cohort study of children who were aged 4-16 years at the time of enrollment in 1983 and were resurveyed in 2001. Respondents reporting a first episode of back pain (n=143) were compared with respondents who had never experienced back pain (n=896). The annual incidence of a first episode of back pain in this sample of young adults was 74.7/1,000. Following adjustment for age, sex, childhood conditions, childhood health status, and measures of early adult health, behavior, socioeconomic status, and work environment, the risk of incident back pain was associated with both low (odds ratio (OR)=1.86, 95% confidence interval (CI): 1.14, 3.03) and moderate/high (OR=1.85, 95% CI: 1.07, 3.02) levels of psychological distress, current heavy smoking (OR=1.85, 95% CI: 1.10, 3.10), lower levels of parental education in childhood (OR=1.72, 95% CI: 1.06, 2.80), and emotional or behavioral disorders in childhood (OR=1.87, 95% CI: 1.02, 3.41). The associations of low childhood socioeconomic status and childhood emotional and behavioral disorders with risk of incident back pain in early adulthood are important findings with implications for better understanding the etiology of soft-tissue disorders.

Acute feed intake and acute-phase protein responses following a lipopolysaccharide challenge in pigs from two dam lines

This study was conducted to evaluate the response of two dam lines of pigs to acute increases of LPS. Acute-phase proteins were also measured to determine their potential use as biological indicators of the immune response. Thirty-six pigs (initial body weight = 21.3 +/- 0.48 kg) were allotted by dam line (Lines 1 and 2) and sex (castrates and gilts) to one of three LPS dose treatments and penned individually. Treatments were a single i.m. injection of 0 (LPS-0), 25 (LPS-25) or 50 microg LPS/kg body weight (BW) (LPS-50). Acute changes in feed intake were related to a pre-injection baseline intake. Feeders were weighed daily to establish baseline feed intake (average daily feed intake -48 to 0 h prior to injection). The acute feed intake response (AFIR) was computed as the average daily feed intake 0-48 h after injection divided by baseline intake. Serum was harvested at time 0 and 48 h after injection. LPS-0 pigs grew faster and consumed more feed than the LPS-25 or LPS-50 pigs (0.79 kg/d versus 0.51 and 0.50 kg/d; 1.15 kg/d versus 0.96 and 0.89 kg/d, respectively; P<0.001). The AFIR of Line 1 castrates and Line 2 gilts was similar for LPS-25 and LPS-50 treatments, while Line 1 gilts and Line 2 castrates had decreased AFIR with increased LPS dose (sex x line x LPS, P<0.05). Three of 18 castrates died but no gilts died following the LPS challenge (P<0.10). Castrates had higher haptoglobin (Hpt) concentrations than gilts on d 0 (18.1 units of absorption/mg of protein versus 13.1 units of absorption/mg of protein; P<0.03). Line 1 pigs had higher C-reactive protein (CRP) concentrations than Line 2 pigs (P<0.05) on d 0. LPS treatment did not change serum concentrations of CRP, Hpt or ceruloplasmin (Cp). However, the change in serum amyloid A (SAA) concentration decreased quadratically (from 0 to 48 h) with increasing LPS dose (P<0.02). This change in SAA was negatively correlated with the AFIR (r= -0.80; P<0.001). In general, castrates appear to be more sensitive to endotoxin challenges than gilts. Serum amyloid A, but not the other acute-phase proteins evaluated, was a good biological indicator of immune system activation following an acute lipopolysaccharide challenge when compared to the acute change in feed intake.

The effects of thermal environment and spray-dried plasma on the acute-phase response of pigs challenged with lipopolysaccharide

Forty barrows (TR4 x C22) were weaned at 17 d of age (BW = 6.27 +/- 0.30 kg), housed (two pigs/pen) in a thermal-neutral environment (TN; constant 26.7 degrees C), and fed diets with or without 7% (as-fed basis) spray-dried plasma (SDP). On d 7, one pig/ pen was moved into a cold environment (CE; constant 15.6 degrees C). Pigs were fitted with jugular catheters on d 11. On d 12, 16 pigs per environment (eight pigs per dietary treatment) were challenged i.v. with 75 microg of lipopolysaccharide (LPS)/kg of BW. Blood samples were collected over a 4.5-h period. Pigs were then killed and tissue samples were harvested for messenger RNA (mRNA) analysis. From d 0 to 7, pigs fed SDP diets had a lower gain:feed ratio (G/F) than pigs fed no SDP (533 +/- 14 vs. 585 +/- 17 g/kg; P < 0.03). Pigs housed in the CE consumed more feed and had a lower G/F than pigs housed in TN from d 7 to 11 (P < 0.001). There were no environment x diet interactions from d 7 to 11 (P > 0.78). Baseline concentrations of serum ACTH and cortisol were lower in the TN pigs than in the CE pigs (P < 0.001). Pigs fed diets without SDP had lower serum cortisol concentrations over the 4.5-h period than pigs fed SDP (time x diet, P < 0.001). Serum concentrations of tumor necrosis factor-alpha (TNF-alpha) were highest for pigs consuming SDP in the CE, whereas there were no differences among the other treatments (time x diet x environment, P < 0.02). Pigs housed in the CE had higher serum interleukin-1beta (IL-1beta) (P < 0.001) and interleukin-6 (IL-6; P < 0.001) than TN pigs. Pigs fed SDP also had slightly higher serum IL-1beta concentrations (P < 0.10) and higher (P < 0.001) IL-6 concentrations than pigs fed no SDP. Pigs fed SDP had 9% lower liver and 13% lower thymus mRNA expression of tumor necrosis factor-alpha (TNF-alpha) than pigs that consumed no SDP (P < 0.06). Liver IL-1beta, IL-6, and LPS-binding protein mRNA were higher in the CE than in the TN (P < 0.03, P < 0.001, and P < 0.05; respectively). In addition, spleen TNF-alpha (P < 0.03) and IL-6 (P < 0.01) mRNA levels were higher in the CE than in the TN. Pigs consuming SDP and challenged with LPS responded with elevated serum concentrations of cortisol and cytokines compared with pigs fed diets with no SDP. Housing pigs in a CE increased the baseline concentrations of ACTH and cortisol, and when coupled with an LPS challenge, resulted in elevated serum and tissue mRNA levels of cytokines. Cold stress and feeding SDP during a LPS challenge may result in increased stress and immune responses in young pigs.

Determinants of duration of disability and return-to-work after work-related injury and illness: challenges for future research

BACKGROUND

The purpose of this review was to identify critical data and research needs in addressing the following question: What are the primary factors that affect the time lost from work, return-to-work (RTW), subsequent unemployment, and changes in occupation after disabling illness or injury?

METHODS

Review of the literature to identify research challenges originating from the multitude of disciplines, data sources, outcome measures, and methodological and analytical problems.

RESULTS

About 100 different determinants of RTW outcomes were identified. Their impact varies across different phases of the disablement process. Recommendations are provided for addressing five selected research challenges.

CONCLUSION

Interdisciplinary research needs to develop a comprehensive conceptual framework. Priority should be given to studies on specific domains of risk factors meeting five selection criteria: amenability to change; relevance to users of research; generalizability across health conditions, disability phases, and settings; "degree of promise" as derived from qualitative exploratory studies; and capacity to improve measurement instruments. Combining qualitative and quantitative research methods is necessary to bridge existing knowledge gaps.

A systematic review of the prognosis of acute whiplash and a new conceptual framework to synthesize the literature

STUDY DESIGN

Systematic review of prognostic studies of acute whiplash.

OBJECTIVES

To update the systematic review on the prognosis of acute whiplash published by the Quebec Task Force on Whiplash-Associated Disorders and to propose a new conceptual framework to conduct systematic reviews on prognosis.

SUMMARY OF BACKGROUND DATA

In 1995, the Quebec Task Force published a systematic review of the literature on whiplash and concluded that its prognosis is favorable. However, few prognostic factors were identified. Recent studies have added to this knowledge, and there is a need to update the review conducted by the Quebec Task Force.

METHODS

A bibliographic search of four electronic databases was performed to identify prognostic studies of acute whiplash published after 1995. The literature was appraised with standard review criteria. The consistency of evidence across studies was assessed. A conceptual framework was designed to classify the literature according to methodologic quality, target population, and phases of investigation.

RESULTS

Thirteen cohort studies were included in the review. The framework used in this study demonstrates that most of the recent prognostic studies are descriptive in nature. The prognosis of acute whiplash varies according to the population sampled and the insurance/compensation system under which individuals are allowed to claim benefits. Besides age, gender, baseline neck pain intensity, baseline headache intensity, and baseline radicular signs and symptoms, there is little consistency in the literature about the prognostic factors for the recovery of whiplash.

CONCLUSIONS

Scant knowledge about the prognosis of whiplash has been gained since the release of the Quebec Task Force report. However, it is becoming obvious that the insurance and compensation systems have a large impact on recovery from acute whiplash injuries. The conceptual framework used in this study demonstrates that large cohort studies investigating a wide range of prognostic factors are necessary to improve the understanding of this problem.

Does how you do depend on how you think you'll do? A systematic review of the evidence for a relation between patients' recovery expectations and health outcomes

BACKGROUND

Most clinicians would probably agree that what patients think will happen can influence what does happen over the clinical course. Yet despite useful narrative reviews on expectancy of therapeutic gain and the mechanisms by which expectancy can affect health outcomes, we were unable to locate a systematic review of the predictive relation between patients' recovery expectations and their health outcomes.

METHODS

We searched MEDLINE for English-language articles published from 1966 to June 1998 with a title or abstract containing at least 1 of the medical subject headings (MeSH) "self-assessment," "self-concept" or "attitude to health," or the MeSH subheading "psychology," and at least 1 word from each of 3 sets: "patient" and similar words; a form of "expectation," "belief" or "prediction"; and a form of "recover," "outcome," "survival" or "improve." Relevant articles contained original research data, measured patients' recovery expectations, independently measured a subsequent health outcome and analyzed the relation between expectations and outcomes. We assessed internal validity using quality criteria for prognostic studies based on 6 categories (case definition; patient selection; extent of follow-up; objective outcome criteria; measurement and reporting of recovery expectations; and analysis).

RESULTS

A total of 1243 titles or abstracts were identified through the computer search, and 93 full-text articles were retrieved. Forty-one of these articles met the relevance criteria, along with 4 additional articles identified through other means. Agreement beyond chance on quality assessments of 18 randomly selected articles was high (kappa = 0.87, p = 0.001). Sixteen of the 45 articles provided moderate-quality evidence and included a range of clinical conditions and study designs; 15 of the 16 showed that positive expectations were associated with better health outcomes. The strength of the relation depended on the clinical conditions and the measured used.

INTERPRETATION

Consistency across the studies reviewed and the evidence they provided support the need for clinicians to clarify patients' expectations and to assist them in having appropriate expectations of recovery. The understanding of the nature, extent and clinical implications of the relation between expectations and outcomes could be enhanced by more conceptually driven and methodologically sound research, including evaluations of intervention effectiveness.

Biomechanical and psychosocial risk factors for low back pain at work

OBJECTIVES

This study determined whether the physical and psychosocial demands of work are associated with low back pain.

METHODS

A case-control approach was used. Case subjects (n = 137) reported a new episode of low back pain to their employer, a large automobile manufacturing complex. Control subjects were randomly selected from the study base as cases accrued (n = 179) or were matched to cases by exact job (n = 65). Individual, clinical, and psychosocial variables were assessed by interview. Physical demands were assessed with direct workplace measurements of subjects at their usual jobs. The analysis used multiple logistic regression adjusted for individual characteristics.

RESULTS

Self-reported risk factors included a physically demanding job, a poor workplace social environment, inconsistency between job and education level, better job satisfaction, and better coworker support. Low job control showed a borderline association. Physical-measure risk factors included peak lumbar shear force, peak load handled, and cumulative lumbar disc compression. Low body mass index and prior low back pain compensation claims were the only significant individual characteristics.

CONCLUSIONS

This study identified specific physical and psychosocial demands of work as independent risk factors for low back pain.

Chiropractors and return-to-work: the experiences of three Canadian focus groups

OBJECTIVES

To explore the views of chiropractors about timely return-to-work in treating patients with musculoskeletal injuries, to identify the approaches used by chiropractors when treating injured workers with musculoskeletal disorders, and to learn about chiropractors' perspectives on the barriers and facilitators of successful return-to-work.

DESIGN

Qualitative study of 3 focus groups of chiropractors.

METHODS

Focus groups of 8 to 11 chiropractors were conducted in 3 large Canadian cities. The selected participants were experienced in treating patients with occupational musculoskeletal injuries. Standard questions were used to collect data. The data from each focus group were coded and analyzed separately and then considered in relation to each other.

RESULTS

The participants indicated that timely return-to-work depends on patients' characteristics, severity of injury, clinical progress, the availability of work accommodation, and clinical judgment. The chiropractors commented that their treatment of injured workers rests on their strength in diagnosis and treatment and on providing patient-centered care. Positive human relations within workplaces and the ability to accommodate the work of an injured worker were described as important in return-to-work programs. The participants believed that a bias against chiropractic is present within the medical profession and workers' compensation boards. They viewed this bias as an important barrier when assisting their patients to successfully return to work.

CONCLUSION

The broad approaches described by the participating chiropractors to return injured workers to work are consistent with those proposed in evidence-based practice guidelines. Better communication among chiropractors, medical doctors, and workers' compensation boards would likely decrease interprofessional tensions and improve the recovery of workers with musculoskeletal injuries.

Cost-effectiveness studies of medical and chiropractic care for occupational low back pain. a critical review of the literature

BACKGROUND CONTEXT

Back pain is the single most costly work-related injury. Chiropractors and physicians are the main primary care providers for occupational low back pain (OLBP), but there is no consensus regarding the relative cost-effectiveness of these two modes of care.

PURPOSE

To critically appraise and synthesize recent literature on the cost-effectiveness of medical and chiropractic care for OLBP, and to propose a cost-effectiveness methodology that integrates epidemiologic and economic methods for future studies.

STUDY DESIGN

Literature review. MEDLINE was searched from 1990 through 1999. Nine articles that met the inclusion criteria were reviewed. The methodological quality of the articles was critically appraised independently by two epidemiologists using standardized review criteria. Two health economists reviewed the studies on cost-effectiveness.

RESULTS

The current literature suggests that chiropractors and physicians provide equally effective care for OLBP but that chiropractic patients are more satisfied with their care. Evidence on the relative costs of medical and chiropractic care is conflicting. Several methodological deficiencies limit the validity of the reviewed studies. No studies combine high-quality cost data with adequate sample sizes and controls for confounding factors.

CONCLUSION

Existing studies fail to clarify whether medical or chiropractic care is more cost effective. We suggest that future studies must combine epidemiologic and economic methods to answer the question adequately.

The association between neck pain intensity, physical functioning, depressive symptomatology and time-to-claim-closure after whiplash

Time-to-claim-closure is a common outcome in cohort studies of whiplash injuries. However, its relationship to health recovery is unknown. We investigated the association between neck pain, physical functioning, depressive symptomatology and time-to-claim-closure in a Saskatchewan cohort of 5398 whiplash claimants in 1994-1995. Participants were surveyed five times over 1 year. In 1995, the insurance system changed from tort to no-fault, eliminating compensation for pain and suffering. Under tort, a 10-point increase in pain reduced the claim-closure rate by 13-24% while a 10-point increase in physical functioning increased it by 17%. Depressive symptomatology reduced the claim-closure rate by 37%. Under no-fault, a 10-point increase in pain reduced the claim-closure rate by 18% while a 10-point increase in physical functioning increased it by 10-35%. The presence of depressive symptomatology reduced the claim-closure rate by 36%. The results suggests lower pain, better function and the absence of depressive symptoms are strongly associated with faster time-to-claim-closure and recovery after whiplash, independent of the insurance system.

Modified work: prevalence and characteristics in a sample of workers with soft-tissue injuries

Modified-work programs are designed to facilitate the return to work for employees with a work-related injury. Although extensive published literature exists that describes and evaluates "ideal" programs, to date there is a paucity of data describing practice. To address this pertinent issue, we administered a survey to a large sample of 1833 workers with soft-tissue injuries in Ontario, Canada, and asked them detailed questions about modified work and employer contact. Our results reveal that most workers (66%) were contacted by someone from their workplace to check on how they were doing. However, only a minority (36%) were offered arrangements by their employer to help them return to work after developing a work-related soft-tissue injury. Most arrangements that were offered to injured workers consisted of such temporary modifications as reduced hours (24%), flexible work hours (25%), or a lighter job (57%) rather than more permanent changes to the way that work is conducted, such as changes to the work layout or equipment (8%). Merely being contacted by the workplace to check on how the worker was doing was not associated with reduced compensation benefit duration. Workplace offers of arrangements to help the worker return to work were associated with reduced compensation benefit duration but were not statistically associated with workers' pain grade.

Historical and cultural roots of drinking problems among American Indians

Roots of the epidemic of alcohol-related problems among many Native North Americans are sought in cultural responses to European arrival, the role of alcohol in frontier society, and colonial and postcolonial policies. Evidence from the historical record is considered within the framework of current social science. Initially, Native American's responses to alcohol were heavily influenced by the example of White frontiersmen, who drank immoderately and engaged in otherwise unacceptable behavior while drunk. Whites also deliberately pressed alcohol upon the natives because it was an immensely profitable trade good; in addition, alcohol was used as a tool of "diplomacy" in official dealings between authorities and natives. The authors argue that further research into the origins of modern indigenous people's problems with alcohol would benefit from an interdisciplinary "determinants of health" approach in which biological influences on alcohol problems are investigated in the context of the cultural, social, and economic forces that have shaped individual and group drinking patterns.

Hepatic hydrothorax: pathogenesis, diagnosis, and management

Hepatic hydrothorax is defined as a pleural effusion in a patient with cirrhosis of the liver and no cardiopulmonary disease. The estimated prevalence of this often debilitating complication in patients with liver cirrhosis is 4% to 10%. Its pathophysiology involves movement of ascitic fluid from the peritoneal cavity into the pleural space through diaphragmatic defects. As a result patients are at increased risk of respiratory infection. Initial management consists of sodium restriction, diuretics, and thoracentesis. A transjugular intrahepatic portosystemic shunt may be required. Because most patients with hepatic hydrothorax have end-stage liver disease, a liver transplant should be considered if these options fail.

Perspectives on prognosis of soft tissue musculoskeletal disorders

This paper reflects on the state of evidence related to the prognosis of soft tissue musculoskeletal disorders. Prediction of the likely clinical course, duration and outcomes for individuals with such disorders is an important task of rehabilitation clinicians. Criteria used to evaluate the validity of evidence on prognosis are reviewed. Application of these criteria to the literature on three soft tissue disorders reveals methodological weaknesses in the majority of existing studies. Yet strengthening the rigour of future research according to clinical epidemiological criteria may not capture the important factors which prolong disability in individuals with soft tissue injuries. Specific considerations related to case definitions, prognostic factors, study design, conceptual frameworks and study setting are recommended.

Effects of glucagon on postprandial carbohydrate metabolism in nondiabetic humans

The present experiments sought to determine whether glucagon concentrations mimicking those observed in people with diabetes mellitus alter postprandial carbohydrate metabolism in nondiabetic humans. We measured the gastric emptying of solids and liquids, the systemic rate of appearance of ingested glucose, and endogenous glucose production either when postprandial suppression of glucagon was prevented by infusing glucagon at a rate of 0.65 ng/kg/min, when postprandial glucagon concentrations were elevated by infusing glucagon at a rate of 3.0 ng/kg/min, or when postprandial suppression of glucagon was permitted by infusion of saline. Despite marked differences in glucagon concentrations, postprandial glucose and insulin concentrations did not differ on any occasion. Although gastric emptying of liquids and solids was comparable on all three occasions, the high-dose, but not the low-dose, glucagon infusion caused a slight delay in the systemic appearance of ingested glucose and a significant decrease (P < .01) in postprandial D-xylose concentrations, suggesting a delay in carbohydrate absorption. However, this was offset by an increase (P < .05) in endogenous glucose production, resulting in no difference in postprandial glucose appearance. We conclude that in the absence of insulin deficiency, neither a lack of suppression of glucagon nor an elevation of glucagon to levels encountered in uncontrolled diabetes mellitus cause postprandial hyperglycemia in nondiabetic humans.

Back pain claim rates and the business cycle

The causes of reported occupational back pain are controversial. Many observers appear to believe that job insecurity increases back pain compensation claims during recessions. The purpose of this study was to formally examine the impact of macro-economic forces-the business cycle-on the incidence of lost-time back pain claim rates in order to elicit clues to both its aetiology and reporting patterns. For Ontario between 1975 and 1993, age- and sex-adjusted lost-time back pain claim rates, stratified by industry sector (construction, manufacturing and trade), were regressed on the unemployment rate of the industry sector using time series methods. As a comparison group, the association between "acute" claim (fractures, lacerations, etc.) and the business cycle was also tested. Both back pain claim rates and acute claim rates increased during boom periods and decreased during recessionary periods. Time series analyses confirmed that these associations were statistically significant. The elasticities between claim rates and the unemployment rate were similar for back pain claims and acute claims. In addition, these associations were consistent in direction across all three industrial sectors tested. These results rebut the view that back pain claims increase during recessionary times.

Disability resulting from occupational low back pain. Part I: What do we know about primary prevention? A review of the scientific evidence on prevention before disability begins

This is the first of two papers that systematically review available scientific evidence on the causes of disability from occupational low back pain, and the effectiveness of interventions to prevent it-before disability begins (primary prevention-Part I) and after its onset (secondary prevention-Part II). This first paper reviews the risk factors for the onset of pain and associated disability followed by a critical summary of intervention studies attempting to achieve prevention and to evaluate the results.

Disability resulting from occupational low back pain. Part II: What do we know about secondary prevention? A review of the scientific evidence on prevention after disability begins

This is the second of two papers that systematically review available scientific evidence on the causes of disability from occupational low back pain, and the effectiveness of interventions to prevent it after its onset (secondary prevention). This paper reviews the national history of how back pain and the risk factors for its extension into chronic disability, followed by a critical summary of intervention studies attempting to reduce the duration of this disability, and to evaluate the results.

Research responses to outbreaks of concern about local environments

Traditional epidemiological approaches based on biomedical models may be limited with respect to their response to "outbreaks of concern" among work-force or community populations. Three published Canadian "outbreaks" were reviewed in this study. In all three instances, research was initiated because lay persons were concerned about either nonspecific symptoms or hazardous exposures, and individuals publicly called for a response. Epidemiologic analyses were inconclusive as to the reasons for the outbreaks, and they contributed little toward the resolution of concerns. There is a need for a fuller recognition of the role of social context and of the action-oriented nature of such research. The elucidation of multifactorial and culturally mediated causation, as well as the development of remedial actions, require a rethinking of research methods. We specifically call for (a) an expansion of the disciplinary base of research teams to include social scientists, and (b) the adoption of combined qualitative and quantitative research approaches.

Using Labour Force Survey and census data to generate denominators for occupational injury rates: an application and expansion of Haggar-Guénette's method

The calculation of rates of occupational injury claims is essential to identify groups at high risk, yet limitations of denominator data have often restricted our capacity to do this. Haggar-Guénette's method of using Statistics Canada's data on paid workers from the Labour Force Survey as denominators has been expanded by incorporating information from the Census. The method is illustrated by calculating denominators for male construction industry workers within the province of Ontario. Information for paid workers employed in construction occupations was derived from the Labour Force Survey to produce denominators for those aged 15-64, overall and by 10-year age groups. Census data on the distribution of construction occupational roles were applied to produce denominators both overall, then simultaneously by age and by occupational role. Advantages and disadvantages, including the limitations or biases due to the differing sources for denominators and numerators are identified.

Quantitative measures of human immunodeficiency virus-specific antibodies predict progression to AIDS

Studies examining specific antibodies directed against antigenic components of human immunodeficiency virus (HIV), as potential markers of progression to AIDS, have reported inconsistent results. We used reflectance densitometry and survival analysis to determine whether single quantitative measures of HIV-specific antibodies predicted progression to AIDS in a prospective cohort of 159 HIV-infected homosexual men. Lowered baseline levels of p24 antibody and p24/gp41 antibody ratio were independent predictors of progression to AIDS and retained statistical significance after simultaneously controlling for CD4:CD8 ratio, age, use of zidovudine, and clinical symptoms. Quantitative measures of p24 antibody and p24/gp41 antibody ratio warrant further study with regards to their clinical application as markers of HIV disease progression.

Mechanism of accelerated gastric emptying of liquids and hyperglycemia in patients with type II diabetes mellitus

BACKGROUND & AIMS

The roles of hyperglycemia in diabetic gastroparesis and gastric delivery in postprandial hyperglycemia of diabetic patients are unclear. The aims of this study were to assess gastric emptying and its relation to postprandial glucose metabolism in patients with asymptomatic non-insulin-dependent diabetes mellitus (NIDDM) and no autonomic neuropathy and to identify motor mechanisms responsible for any accelerated gastric emptying.

METHODS

Autonomic function, gastric emptying, postprandial glucose metabolism, and hormone levels (glucagon, insulin, cholecystokinin, glucose-dependent insulinotropic polypeptide, neurotensin, and peptide YY) were assessed in healthy volunteers and patients with NIDDM. In a second study, gastric tone and motility were measured in patients with accelerated gastric emptying and in controls.

RESULTS

Gastric emptying of solids did not differ in the two groups, but liquids emptied faster in patients with NIDDM (P < 0.02). The rate of entry of ingested glucose into the systemic circulation was similar, but higher postprandial glucagon and lower insulin concentrations led to greater (P < 0.01) postprandial hepatic glucose release. Levels of other enteropeptides, gastric accommodation, and antral motility were similar, but patients with NIDDM had greater proximal gastric phasic contractions than controls (P < 0.05).

CONCLUSIONS

Excessive hepatic glucose release, not rapid entry of ingested glucose, is the primary cause of postprandial hyperglycemia in patients with NIDDM. Accelerated gastric emptying in patients with nonneuropathic NIDDM is associated with increased proximal stomach phasic contractions.

Methodological issues in assessing reproducibility--a comparative study of various indices of reproducibility applied to repeat ELISA serologic tests for Lyme disease

This study applies and evaluates a variety of different measures of reproducibility. As an example, repeat enzyme-linked immunosorbent assays (ELISA) for antibodies to Borrelia burgdorferi, the etiologic agent of Lyme disease, are used. These repeat tests were part of the 1991 Quality Control Assessment of provincial laboratories that was carried out by the Laboratory Centre for Disease Control (Ottawa). Twenty-seven sera from cases and non-cases were tested by three laboratories, and two laboratories repeated the tests once. Methodological issues discussed include: different methods of assessing reproducibility in the continuous scale; whether reproducibility should be assessed with data in continuous or categorical form; problems assessing the reproducibility of data that has been standardized using a calibration-regression line; and problems with external generalizability of reproducibility studies of rare diseases. The authors conclude that the statistical method used to assess the reproducibility of a test must be adjusted to suit individual study designs and data, and the usage of the test.

Technical note: a new device for performing sinograms--the Frank catheter

Usually sinography is a difficult and messy investigation, in that most of the contrast medium seeps past the Foley catheter balloon and out of the orifice. A new sinogram catheter has been devised to overcome this problem.

Patient consent to observation. Responses to requests for written consent in an academic family practice unit

OBJECTIVE

To examine patient rates of consent to observation and response to being asked for written consent.

DESIGN

Patients were asked to provide written consent for a supervising physician to observe a resident performing a physical examination, or for both direct observation and videotaping of the visit. After the visit, all patients were interviewed, and patients who had given written consent completed a questionnaire.

SETTING

The family practice unit at a teaching hospital affiliated with the University of Toronto.

PARTICIPANTS

A representative sample of new and returning patients.

MAIN OUTCOME MEASURES

Patient consent to observation or videotaping.

RESULTS

Most patients (92.2%) agreed to be observed. Of those asked only for consent to observe, 97.3% agreed. Of those asked for consent to observe and videotape, 85.2% agreed. When specifically asked, 22% of patients who agreed to observation expressed concerns.

CONCLUSION

We must devise clear policies and procedures for obtaining patient consent that are both sensitive to patients' concerns and administratively effective.