The odds ratio (OR) is probably the most widely used index of effect size in epidemiological studies. The difficulty of interpreting the OR has troubled many clinical researchers and epidemiologists for a long time. We propose a new method for interpreting the size of the OR by relating it to differences in a normal standard deviate. Our calculations indicate that OR = 1.68, 3.47, and 6.71 are equivalent to Cohen's d = 0.2 (small), 0.5 (medium), and 0.8 (large), respectively, when disease rate is 1% in the nonexposed group; Cohen's d   0.8 when OR > 5.

https://www.tandfonline.com/doi/pdf/10.1080/03610911003650383

How Big is a Big Odds Ratio? Interpreting the Magnitudes of Odds Ratios in Epidemiological Studies

Aims To determine the incidence of, and clinically relevant risk factors for, new foot ulceration in a large cohort of diabetic patients in the community healthcare setting.

Methods Diabetic patients (n = 9710) underwent foot screening in six districts of North-west England in various healthcare settings. All were assessed at baseline for demographic information, medical and social history, neuropathy symptom score, neuropathy disability score, cutaneous pressure perception (insensitivity to the 10 g monofilament), foot deformities, and peripheral pulses. Two years later, patients were followed up via postal questionnaire to determine the incidence of new foot ulcers. Cox’s proportional hazards regression analysis was used to determine the independent, relative risk of baseline variables for new foot ulceration.

Results New foot ulcers occurred in 291/6613 patients who completed and returned their 2-year follow-up questionnaire (2.2% average annual incidence). The following factors were independently related to new foot ulcer risk: ulcer present at baseline (relative risk (95% confidence interval)) 5.32 (3.71–7.64), past history of ulcer 3.05 (2.16–4.31), abnormal neuropathy disability score (≥ 6/10) 2.32 (1.61–3.35), any previous podiatry attendance 2.19 (1.50–3.20), insensitivity to the 10 g monofilament 1.80 (1.36–2.39), reduced pulses 1.80 (1.40–2.32), foot deformities 1.57 (1.22–2.02), abnormal ankle reflexes 1.55 (1.01–2.36) and age 0.99 (0.98–1.00).

Conclusions More than 2% of community-based diabetic patients develop new foot ulcers each year. The neuropathy disability score, 10 g monofilament and palpation of foot pulses are recommended as screening tools in general practice.

The North-West Diabetes Foot Care Study: incidence of, and risk factors for, new diabetic foot ulceration in a community-based patient cohort.

Background
Lay health workers (LHWs) are widely used to provide care for a broad range of health issues. Little is known, however, about the effectiveness of LHW interventions.

Objectives
To assess the effects of LHW interventions in primary and community health care on maternal and child health and the management of infectious diseases.

Search methods
For the current version of this review we searched The Cochrane Central Register of Controlled Trials (including citations uploaded from the EPOC and the CCRG registers) (The Cochrane Library 2009, Issue 1 Online) (searched 18 February 2009); MEDLINE, Ovid (1950 to February Week 1 2009) (searched 17 February 2009); MEDLINE In-Process & Other Non-Indexed Citations, Ovid (February 13 2009) (searched 17 February 2009); EMBASE, Ovid (1980 to 2009 Week 05) (searched 18 February 2009); AMED, Ovid (1985 to February 2009) (searched 19 February 2009); British Nursing Index and Archive, Ovid (1985 to February 2009) (searched 17 February 2009); CINAHL, Ebsco 1981 to present (searched 07 February 2010); POPLINE (searched 25 February 2009); WHOLIS (searched 16 April 2009); Science Citation Index and Social Sciences Citation Index (ISI Web of Science) (1975 to present) (searched 10 August 2006 and 10 February 2010). We also searched the reference lists of all included papers and relevant reviews, and contacted study authors and researchers in the field for additional papers.

Selection criteria
Randomised controlled trials of any intervention delivered by LHWs (paid or voluntary) in primary or community health care and intended to improve maternal or child health or the management of infectious diseases. A 'lay health worker' was defined as any health worker carrying out functions related to healthcare delivery, trained in some way in the context of the intervention, and having no formal professional or paraprofessional certificate or tertiary education degree. There were no restrictions on care recipients.

Data collection and analysis
Two review authors independently extracted data using a standard form and assessed risk of bias. Studies that compared broadly similar types of interventions were grouped together. Where feasible, the study results were combined and an overall estimate of effect obtained.

Main results
Eighty-two studies met the inclusion criteria. These showed considerable diversity in the targeted health issue and the aims, content, and outcomes of interventions. The majority were conducted in high income countries (n = 55) but many of these focused on low income and minority populations. The diversity of included studies limited meta-analysis to outcomes for four study groups. These analyses found evidence of moderate quality of the effectiveness of LHWs in promoting immunisation childhood uptake (RR 1.22, 95% CI 1.10 to 1.37; P = 0.0004); promoting initiation of breastfeeding (RR = 1.36, 95% CI 1.14 to 1.61; P < 0.00001), any breastfeeding (RR 1.24, 95% CI 1.10 to 1.39; P = 0.0004), and exclusive breastfeeding (RR 2.78, 95% CI 1.74 to 4.44; P <0.0001); and improving pulmonary TB cure rates (RR 1.22 (95% CI 1.13 to 1.31) P <0.0001), when compared to usual care. There was moderate quality evidence that LHW support had little or no effect on TB preventive treatment completion (RR 1.00, 95% CI 0.92 to 1.09; P = 0.99). There was also low quality evidence that LHWs may reduce child morbidity (RR 0.86, 95% CI 0.75 to 0.99; P = 0.03) and child (RR 0.75, 95% CI 0.55 to 1.03; P = 0.07) and neonatal (RR 0.76, 95% CI 0.57 to 1.02; P = 0.07) mortality, and increase the likelihood of seeking care for childhood illness (RR 1.33, 95% CI 0.86 to 2.05; P = 0.20). For other health issues, the evidence is insufficient to draw conclusions regarding effectiveness, or to enable the identification of specific LHW training or intervention strategies likely to be most effective.

Authors' conclusions
LHWs provide promising benefits in promoting immunisation uptake and breastfeeding, improving TB treatment outcomes, and reducing child morbidity and mortality when compared to usual care. For other health issues, evidence is insufficient to draw conclusions about the effects of LHWs.

/pdf/lay-health-workers-in-primary-and-community-health-care-for-561d75zkrw.pdf

Lay health workers in primary and community health care for maternal and child health and the management of infectious diseases.

Study Design. A double-blind, randomized controlled trial of a novel educational booklet compared with a traditional booklet for patients seeking treatment in primary care for acute or recurrent low back pain.

Objective. To test the impact of a novel educational booklet on patients' beliefs about back pain and functional outcome.

Summary of Background Data. The information and advice that health professionals give to patients may be important in health care intervention, but there is little scientific evidence of their effectiveness. A novel patient educational booklet, The Back Book, has been developed to provide evidence-based information and advice consistent with current clinical guidelines.

Methods. One hundred sixty-two patients were given either the experimental booklet or a traditional booklet. The main outcomes studied were fear-avoidance beliefs about physical activity, beliefs about the inevitable consequences of back trouble, the Roland Disability Questionnaire, and visual analogue pain scales. Postal follow-up response at 1 year after initial treatment was 78%.

Results. Patients receiving the experimental booklet showed a statistically significant greater early improvement in beliefs which was maintained at 1 year. A greater proportion of patients with an initially high fear-avoidance beliefs score who received the experimental booklet had clinically important improvement in fear-avoidance beliefs about physical activity at 2 weeks, followed by a clinically important improvement in the Roland Disability Questionnaire score at 3 months. There was no effect on pain.

Conclusion. This trial shows that carefully selected and presented information and advice about back pain can have a positive effect on patients' beliefs and clinical outcomes, and suggests that a study of clinically important effects in individual patients may provide further insights into the management of low back pain.

Nonspecific low back pain is a common and recurring symptom that most people usually deal with themselves and for which there is no effective cure. Hence, the information and advice that health professionals give to patients may be a potent element of the health care intervention. Von Korff and Saunders 36 and Bush et al 12 found that one of the main reasons patients consult physicians is to seek information and reassurance. Bush et al 12 suggested that these patients have practical and realistic desires to learn about their low back pain, what to expect, and what they can do about it. There is some evidence that greater congruence among the patient's and clinician's perception of the problem, the prognosis for the disorder, and its long-term management is associated with higher patient satisfaction and better short-term outcomes. 14

Qualitative studies 8,33 have demonstrated the complexity and heterogeneity of patients' perceptions of back pain, which may raise questions about how easily these can be modified by simple information and advice. Deyo and Diehl 18 and Bush et al 12 found that, for patients in the United States, the most frequent reason for dissatisfaction with medical care was failure to receive an adequate explanation of their back pain. Patients who believed that the physician's explanation was inadequate wanted more diagnostic tests, did not cooperate as well with treatment, and had poorer clinical outcomes at 3 weeks. Skelton et al 33 found that patients in the United Kingdom were skeptical of medical explanations for their back pain either because they doubted its validity or because it did not fit their own understanding of the problem. Borkan et al 8 found that Israeli patients also were quite critical of the medical system and more interested in what works.

The first U.S. and U.K. clinical guidelines for acute low back pain 3,16 recommended that patients should be given accurate and up-to-date information and advice about back pain and its management; however, that recommendation was based on theoretical considerations and general clinical consensus rather than on any firm scientific evidence that such information improves outcomes. These guidelines gave few practical details on precisely what the content of that information and advice should be, apart from general reassurance about the absence of serious disease and that most back pain improves quickly with simple symptomatic measures and activity modification. There has been a progressive shift in subsequent international guidelines. 10 Based on additional evidence that is now available, 40 the more recent U.K. 31 and New Zealand 2 guidelines suggest that the physician provide more positive advice to stay active and continue ordinary activities as normally as possible. The New Zealand guidelines also provide a detailed assessment of psychosocial yellow flags (risk factors for chronic pain and disability) and suggest general behavioral principles for how patients with these features should be managed. 23

Discussion at the Second International Forum for Primary Care Research on Low Back Pain 9 identified the continuing need for a simple and convincing explanation of back pain that is acceptable to patients and that would form a logical basis for active management. Most guidelines recommend that printed educational material should be made available, though this recommendation is based on limited evidence. 10 There are hundreds of leaflets and booklets about back pain, but remarkably few have been submitted to any sort of scientific evaluation. 11 Roland and Dixon 28 reported on the only randomized controlled trial (RCT) of a traditional clinical booklet that showed any significant impact on patients: those receiving the booklet consulted less frequently and had fewer specialist referrals for back pain over the next year. Cherkin et al 15 reported on an RCT that compared a 15-minute session with an educational nurse with a booklet that was similar to the material accompanying the Agency for Health Care Policy and Research (AHCPR) guidelines. 3 The nurse intervention yielded higher patient satisfaction, perceived knowledge, and exercise participation in the short term. The booklet showed similar trends, but they did not reach statistical significance compared with the outcomes of usual care. Neither of these trials showed any effect of a booklet on pain or functional status.

The aim of the current study was to determine the impact of a novel educational booklet on the beliefs and functional outcome of patients seeking treatment in primary care for an acute or recurrent episode of low back pain.

Information and advice to patients with back pain can have a positive effect. A randomized controlled trial of a novel educational booklet in primary care.

BACKGROUND
Lay health workers (LHWs) are widely used to provide care for a broad range of health issues. However, little is known about the effectiveness of LHW interventions.


OBJECTIVES
To assess the effects of LHW interventions in primary and community health care on health care behaviours, patients' health and wellbeing, and patients' satisfaction with care.


SEARCH STRATEGY
We searched the Cochrane Effective Practice and Organisation of Care and Consumers and Communication specialised registers (to August 2001); the Cochrane Central Register of Controlled Trials (to August 2001); MEDLINE (1966- August 2001); EMBASE (1966-August 2001); Science Citations (to August 2001); CINAHL (1966-June 2001); Healthstar (1975-2000); AMED (1966-August 2001); the Leeds Health Education Effectiveness Database and the reference lists of articles.


SELECTION CRITERIA
Randomised controlled trials of any intervention delivered by LHWs (paid or voluntary) in primary or community health care and intended to promote health, manage illness or provide support to patients. A 'lay health worker' was defined as any health worker carrying out functions related to health care delivery; trained in some way in the context of the intervention; and having no formal professional or paraprofessional certificated or degreed tertiary education. There were no restrictions on the types of consumers.


DATA COLLECTION AND ANALYSIS
Two reviewers independently extracted data onto a standard form and assessed study quality. Studies that compared broadly similar types of interventions were grouped together. Where feasible, the results of included studies were combined and an estimate of effect obtained.


MAIN RESULTS
Forty three studies met the inclusion criteria, involving more than 210,110 consumers. These showed considerable diversity in the targeted health issue and the aims, content and outcomes of interventions. Most were conducted in high income countries (n=35), but nearly half of these focused on low income and minority populations (n=15). Study diversity limited meta-analysis to outcomes for five subgroups (n=15 studies) (LHW interventions to promote the uptake of breast cancer screening, immunisation and breastfeeding promotion [before two weeks and between two weeks and six months post partum] and to improve diagnosis and treatment for selected infectious diseases). Promising benefits in comparison with usual care were shown for LHW interventions to promote immunisation uptake in children and adults (RR=1.30 [95% CI 1.14, 1.48] p=0.0001) and LHW interventions to improve outcomes for selected infectious diseases (RR=0.74 [95% CI 0.58, 0.93) p=0.01). LHWs also appear promising for breastfeeding promotion. They appear to have a small effect in promoting breast cancer screening uptake when compared with usual care. For the remaining subgroups (n=29 studies), the outcomes were too diverse to allow statistical pooling. We can therefore draw no general conclusions on the effectiveness of these subgroups of interventions.


AUTHORS' CONCLUSIONS
LHWs show promising benefits in promoting immunisation uptake and improving outcomes for acute respiratory infections and malaria, when compared to usual care. For other health issues, evidence is insufficient to justify recommendations for policy and practice. There is also insufficient evidence to assess which LHW training or intervention strategies are likely to be most effective. Further research is needed in these areas.

Lay health workers in primary and community health care : Cochrane systematic review. Commentary

EDITOR—A news item stated that “a review article written by authors with affiliations to the tobacco industry is 88 times more likely to conclude that passive smoking is not harmful than if the review was written by authors with no connection to the tobacco industry.”1 We are concerned that readers may have interpreted this huge effect at face value. The proportions …

Odds ratios should be avoided when events are common

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Odds ratios should be avoided when events are common