Evidence Digest

Hot Off the Press: The Latest SystematicReviews to Guide Best Practice

Bernadette Mazurek Melnyk, RN, PhD, CPNP/NPP, FAAN, FNAP

The purpose of the Evidence Digest, a recurring col-umn in Worldviews, is to provide concise summaries

of well-designed/clinically important recent studies alongwith implications for practice, research, administration,and/or health policy. Articles highlighted in this columnmay include quantitative and qualitative studies, system-atic and integrative reviews, as well as consensus state-ments by expert panels. Along with relevant implications,the level of evidence generated by the studies or reportshighlighted in this column is included at the end of eachsummary so that readers can integrate the strength of evi-dence into their healthcare decisions.

This column features all recently published systematicreviews, which are typically Level 1 evidence, i.e., thestrongest level of evidence to guide clinical practice (Mel-nyk & Fineout-Overholt 2005).

PHYSICAL ACTIVITY AND BREASTCANCER

Monninkhof E.M., Elias S.G., Vlems F.A., van der TweelI., Schuit A.J., Voskuil D.W. & van Leeuwen F.E. (2007).Physical activity and breast cancer: A systematic review.Epidemiology, 18(1), 137–157.

Purpose. This systematic review was conducted to pro-vide an update of epidemiological evidence to determinewhether a relationship exists between physical activity andbreast cancer risk.

Design. Systematic review, including a meta-analysis.Search Strategy/Methods. A search for studies was con-

ducted on PubMed through February of 2006 using thekeywords physical activity or exercise, physical or exer-cises, physical or physical exercise, or physical exercises orsedentary lifestyle, and breast neoplasms or cancer. All co-hort and case–control studies that assessed total or leisuretime activities in relation to the occurrence or mortality ofbreast cancer were included.

Bibliographies also were hand-searched for additionalpapers. Two reviewers independently selected studies tobe included in the review. The inclusion criteria were (1)case–control or cohort studies that were assessing the re-

Copyright ©2007 Sigma Theta Tau International1545-102X/07

lationship between physical activity and breast cancer infemales or males, (2) incidence, prevalence, or mortalitywere included as the end point, (3) more than 10 cancercases in the analysis, and (4) published in English. Addi-tionally, only studies assessing leisure time activity or to-tal activity (i.e., occupational and nonoccupational) wereincluded. Data extraction and quality assessment of thestudies were independently performed by two reviewersand disagreement was resolved by a third reviewer. Inter-rater agreement ranged from 92% to 94% for the cohort andcase studies, respectively. The authors developed a qualityscoring system for cohort and case–control studies.

Findings. Nineteen cohort studies and 29 case–controlstudies were included in the review. The evidence revealeda strong inverse relationship between physical activity andpostmenopausal breast cancer (i.e., as physical activityincreased, breast cancer decreased), with risk reductionsranging from 20% to 80%. The relationship was muchweaker in premenopausal breast cancer, with a 15% to 20%risk reduction. Therefore, the authors determined the evi-dence to be inconclusive in premenopausal women. Therewas a dose response found in about half of the higher-quality studies in that the analysis indicated a 6% (95%confidence interval = 3–8%) decrease in breast cancer riskfor each additional hour of sustained physical activity byindividuals each week.

Commentary with Implications for Clinical Prac-tice. This was a rigorously conducted systematic re-view and meta-analysis that revealed strong support-ing evidence for a relationship between physical activityand breast cancer reduction in postmenopausal women.Since breast cancer is a leading cause of death in women,it is important that this evidence be shared with them byhealthcare providers, although it should be recognizedthat information alone is typically not enough of an in-tervention for individuals to change their behavior (inthis case, to exercise more). Therefore, promising tech-niques such as motivational interviewing should be usedwith postmenopausal women who do not exercise to en-hance their ability to engage in regular physical activity,not only to reduce breast cancer risk, but also for other

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evidence-based benefits of exercise (e.g., reductions instress, blood pressure, and obesity). It should be notedthat since the studies in the review were not random-ized controlled trials (RCTs), only a relationship betweenthese two factors can be supported, not a causal pathway.

EFFICACY OF HOMEOPATHICTREATMENTS FOR CHILDREN AND

ADOLESCENTS

Altunc U., Pittler M.H. & Ernst E. (2007). Homeopathy forchildhood and adolescence ailments: Systematic review ofrandomized clinical trials. Mayo Clinic Proceedings, 82(1),69–75.

Purpose. The purpose of this systematic review was todetermine whether homeopathic treatments for child andadolescents ailments are effective in improving health out-comes.

Design. Systematic review.Search Strategy/Methods. Data bases searched through

January of 2006 included MEDLINE, EMBASE, AMED,CINAHL, Cochrane Central, British Homeopathic Library,ClinicalTrials.gov, and the UK National Research Regis-ter. References cited by the studies also were checkedfor relevant publications. Inclusion criteria included alldouble-blind, placebo-controlled randomized controlledtrials (RCTs) that studied children and adolescents, 0–19 years of age. Studies excluded from the review werethose that included youth who were older than 19 yearsof age. Two of the authors assessed methodological qual-ity of the studies using a systematic process by Jadad etal. (1996) that quantifies the likelihood of bias based on adescription of randomization, blinding, and withdrawals.The third author validated the assessment. Disagreementswere discussed and resolved.

Findings. Three-hundred and twenty-six articles wereidentified and 91 were retrieved for systematic evalua-tion. A total of 16 RCTs were included in the review.Only two conditions (i.e., attention deficit/hyperactivitydisorder [AD/HD] and acute childhood diarrhea) were as-sessed in more than two double-blind RCTs. The evidencefor homeopathic treatment of AD/HD and acute child-hood diarrhea was mixed, with both positive and negativeoutcomes. For asthma, upper respiratory tract infection,and adenoid vegetation, two trials each were found withno effect for homeopathic remedies compared to place-bos. A single RCT tested homeopathy for four conditions(i.e., acute otitis media, conjunctivitis, postoperative pain-agitation syndrome, and warts), with no significant dif-ferences in outcomes between the treatment and placebogroups.

Commentary with Implications for Clinical Practiceand Future Research. A major strength of this systematicreview is that only double-blind RCTs were included,which is the strongest design for establishing cause andeffect relationships and controlling for confounding vari-ables. Therefore, the results of the review are likely tobe valid (i.e., as close to the truth as possible). Find-ings indicate that there is no solid evidence to sup-port the efficacy of homeopathic remedies for commonchildhood illnesses and conditions. This is a very im-portant finding as use of homeopathy in children andadolescents among parents is growing. Although manyindividuals believe that homeopathic remedies are rel-atively safe, use of these treatments could delay treat-ment of potentially serious conditions in children andadolescents. Therefore, healthcare providers need to in-form parents that evidence does not currently supportthe use of homeopathy in the treatment of child andadolescent health conditions. Because only single RCTshave been conducted for various pediatric and adoles-cent illnesses and conditions, there is a need for fu-ture rigorously designed RCTs to test the efficacy ofhomeopathy on child and adolescent health outcomes.

FALL PREVENTION IN HOSPITALS ANDLONG-TERM CARE SETTINGS

Oliver D., Connelly J.B., Victor C.R., Shaw F.E., WhiteheadA., Genc Y., Vanoli A., Martin F.C. & Gosney M.A. (2006,8 December). Strategies to prevent falls and fractures inhospitals and effect of cognitive impairment: Systematicreview and meta-analyses. BMJ. Retrieved March 1, 2007,from doi:10.1136/bmj.39049.706493.55.

Purpose. The purposes of this systematic review were toevaluate strategies to prevent falls or fractures in residentsin care homes and hospital inpatients as well as to inves-tigate the effect of dementia and cognitive impairment onfalls.

Design. Systematic review, including a meta-analysis.Search Strategy/Methods. The Cochrane Database, Clin-

ical Trials Register, Medline, CINAHL, Embase, PsychInfowere searched along with hand searching of references fromreviews and guidelines to January of 2005. Several keywords were used, including accidental fall, fracture, hos-pital, residential facilities, care homes, clinical trials, andprotective devices. Inclusion and exclusion criteria weredeveloped. Randomized clinical trials were included alongwith case–control studies and observational cohort studies.The quality score of Downs and Black (1998) was used toassess papers because it facilitates the assessment of mul-tiple types of designs. One of three pairs of peer assessors

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scored each study and extracted data. Each pair workedindependently.

Findings. The authors identified 1,207 references, in-cluding 115 systematic reviews, expert reviews or guide-lines. Of 92 papers that were yielded, 43 were includedin this review. A meta-analysis for multifaceted interven-tions in the hospital (13 studies) showed a rate ratio of0.82 (95% confidence interval of 0.68–0.99) for falls, butno significant effect on the number of fallers or fractures.Regarding hip protectors in care homes (11 studies), therate ratio for hip fractures was 0.67, but there was nosignificant effect on falls and not enough studies on fall-ers. For all other interventions (e.g., multifaceted inter-ventions in care homes, fall arm devices in either set-ting; exercise; calcium/vitamin D supplementation), meta-analysis was not suitable because of inadequate numbersof studies or showed no significant effect on falls, fallers,orfractures.

Commentary with Implications for Clinical Practiceand Administration. Falls are common place in hospi-tals as well as care homes/long-term care settings. Manyfalls lead to fractures, which are associated with adversehealth and cost outcomes, including impaired function-ing, depression, and lengthier hospital stays. Therefore,it is important for nurses and other healthcare providersto implement evidence-based interventions to preventfalls across the care continuum.

Overall, this was a well designed and conducted meta-analysis that showed there is some evidence to supportthat multifaceted interventions in the hospital reducethe number of falls. However, not all the studies in-cluded in the meta-analysis were RCTs, which slightlyweakens the strength of the evidence summarized. Ad-ditionally, the types of multifaceted interventions in thestudies varied (e.g., risk factor assessment, care plan-ning, removal of physical restraints, changes in the phys-ical environment). Therefore, it would be difficult forhospitals to reproduce the interventions and expect thesame outcomes, since it is not known from this reviewexactly which components of the multifaceted inter-ventions produce the best outcomes. Future RCTs areneeded to be able to determine which combinations ofinterventions lead to a reduction in falls and fractures.Additional trials also are needed to determine the effi-cacy of interventions specifically designed for patientswith cognitive impairment.

There seems to be good evidence that the use of hipprotectors in care homes prevents hip fractures. There-fore, they should be used for those patients who are athighest risk for falls. However, there was insufficient

evidence to support other single interventions in hospi-tals or care homes to prevent falls and fractures.

There is also little evidence to support the im-plementation of multifaceted interventions in carehomes. Long-term care settings that are currently im-plementing multifaceted interventions may be expend-ing unnecessary costs without much true benefit.

INTERVENTIONS TO PREVENT TYPE 2DIABETES

Gillies C.L., Abrams K.R., Lambert P.C., Cooper N.J., Sut-ton A.J., Hsu R.T., & Khunti K. (2007). Pharmacologi-cal and lifestyle interventions to prevent or delay type 2diabetes in people with impaired glucose tolerance: Sys-tematic review and meta-analysis. BMJ. 334(7588): 299.Retrieved January 19, 2007, from doi:10–1136/bmj.39063–689375.55.

Purpose. The purpose of this systematic review was toprevent or delay type 2 diabetes in people with impairedglucose tolerance.

Design. Systematic review, including a meta-analysis.Search Strategy/Methods. The Cochrane Library, Med-

line, and Embase were searched through July of 2006. Ref-erence lists of the studies identified were checked as wellas experts were consulted to help identify further studies.The RCTs filter was used when searching the Cochranedatabase. Key search words included type 2 diabetes andprevention as well as clinical terms for impaired glucose tol-erance. Inclusion criteria for the review consisted of RCTsthat implemented interventions to delay or prevent type 2diabetes with individuals who had impaired glucose toler-ance. The outcomes measure was development of diabetes.Two of the authors independently assessed all the studiesfor quality, using the Jadad score, as well as assessed themfor concealment of allocation to study group. Furthermore,two authors independently extracted data on the develop-ment of type 2 diabetes.

Findings. Twenty-one RCTs met the review’s inclusioncriteria, and 17 of them with 8,084 subjects were in-cluded in the meta-analysis because they reported results inenough detail to include them in the analysis. The pooledhazard ratios were (1) 0.51 for lifestyle interventions versus0.70 for standard advice; (2) 0.70 for oral diabetes drugsversus placebo-control, and (3) 0.32 for the herbal remedyjiangtang bushen recipe versus standard diabetes advice.

Commentary with Implications for Clinical Practice.This meta-analysis was rigorously conducted and in-cluded only RCTs, the strongest level of evidence tosupport cause and effect relationships. The evidence

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supports that lifestyle interventions (e.g., diet and ex-ercise) seem to be just as effective in preventing type2 diabetes as pharmacological interventions that couldproduce adverse side effects.

Again, it is very important for providers to in-form their patients of this evidence as well as im-plement evidence-based strategies to assist them inmaking lifestyle changes that are often difficult forpatients to sustain. Ongoing support and follow-up while patients are making challenging lifestylebehaviors could assist them in sustaining change.

ReferencesDowns S.H., & Black N. (1998). The feasibility of creat-

ing a checklist for the assessment of the methodologicalquality both of randomized and non-randomised stud-ies of healthcare interventions. Journal of Epidemiology& Community Health, 52, 377–384.

Jadad A.R., Moore R.A. & Carroll D. (1996). Assessingthe quality of reports of randomized clinical trials: Isblinding necessary? Control Clinical Trials, 17, 1–12.

Melnyk B.M. & Fineout-Overholt E. (2005). Evidence-based practice in nursing and healthcare. A guide to bestpractice. Philadelphia: Lippincott, Williams & Wilkins.

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