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How large is the intervention or treatment effect?
- September 4, 2019
- Posted by: kajo
About 200,000 healthcare-associated infections (HAIs) are acquired by patients whilst receiving some form of health care in Australia in a one year period (AIHW, 2011). National hand hygiene compliance rates are low, 68.3%, which is concerning given that hand hygiene is the single most important task health care workers can to do prevent HAIs (Girou, Loyeau, Legrand, Oppein, & Brun-Buisson, 2002, p.362). The purpose of this report is to investigate the best methods of hand hygiene to decrease the rate of cross-infection in a hospital setting. To focus the search, this report defines ‘best methods of hand hygiene as the best products to wash ones hands with. Therefore, methods of hand-drying and hand washing protocols are excluded, as well as literature discussing compliance rates and educational interventions.
Practice Question: what are the best methods of hand hygiene to decrease the rate of cross-infection in a hospital setting?
Population: hospital-based personnel, i.e. health-care workers, students.
Intervention: products to wash your hands with, including liquid soap, 70% alcohol based hand rub, chlorhexidine gluconate 4%, and 10% povidone-iodine. (N.B. Interventions of compliance, education and hand-drying were NOT measured).
Control: other products to wash your hands with.
Outcome: infection rates and microbial counts on hands.
Type of study: randomised-controlled trial or experimental studies.
The Search Process: used keywords (or MESH/subject headings) combined with Boolean phrases “and”, then limited the final result to randomised-controlled trial.
1. Hand hygiene
2. Cross infection
3. Hospital units or hospitals
4. Hospital* or unit*
5. 3 or 4
6. 1 and 2 and 5
7. Limit 6 to randomised-controlled trials (RCTs), human subjects and English.
•Inclusion criteria: RCTs or experimental studies, English and human subjects.
•Exclusion criteria: non-English studies, non-human subjects, studies below level II (controlled trial without randomisation, case-control or cohort study, systematic review of qualitative or descriptive studies, qualitative or descriptive study, expert opinion or consensus).
Hand-drying, hand-washing protocols, compliance and educational interventions were not made exclusion criteria by applying limits to the database or negative keywords in the initial search. Instead the abstracts of each article from the final search result were read and assessed for appropriateness (screening), as the number generated was a manageable size to appraise (n=77, see flow diagram on next page). 71 of these 77 articles were excluded, essentially because they focused on compliance, educational interventions, hand drying methods, and hand-washing protocols. It was established at the beginning of the report that ‘best methods of hand hygiene was defined as the best products to wash ones hands, which guided the inclusion and exclusion criteria. Six full-text articles were printed; with one of these articles being excluded as the setting was a university campus instead of a hospital setting (incorrect population). The five studies that were kept investigated the best methods of hand hygiene (i.e. different products to wash ones hands) to decrease the rate of cross-infection in a hospital setting.
•Study types included: level II studies – RCTs or experimental studies.
•Places/databases searched: Pubmed, CINAHL, and Medline.
Critical Appraisal Process: Is the study design valid?
N.B. The criteria used to evaluate the remaining five study designs validity was that used by Fineout-Overholt, Melnyk, Stillwell & Williamson (2010), prescribed reading 2 of the week 7 reading list NURS1007.
Rapid Critical Appraisal Questions (Fineout-Overholt et al., 2010, pp. 44-45):
1. Are the results of the study valid?
A. Were the subjects randomly assigned to the intervention and control groups?
B. Was random assignment concealed from the individuals enrolling the subjects?
C. Were the subjects and providers blind to the study group?
D. Were reasons given to explain why subjects didnt complete the study?
E. Were the follow-up assessments long enough to fully study the effects of the intervention?
F. Were the subjects analysed in the group to which they were randomly assigned?
This method of analysis is termed “intention-to-treat analysis”, whereby researchers keep participants in their assigned groups when conducting the analysis and intends to reduce possible bias (Fineout-Overholt et al., 2010, p. 46).
G. Was the control group appropriate?
H. Were the instruments used to measure the outcomes valid and reliable?
I. Were the demographics and baseline clinical variables of the subjects in each of the groups similar?
2. What are the results?
A. How large is the intervention or treatment effect?
Indicated by the odds ratio (OR), which measures the association between an intervention and an outcome (Fineout-Overholt et al., 2010, p. 46).
B. How precise is the intervention or treatment?
The intervention or treatment is significant if the P-value is less than 0.05 (P < 0.05) and the confidence interval (CI) for OR does not include 1.0, meaning the findings are reliable. Findings that are not statistically significant could have been obtained by chance, so cannot be confidently put into practice (Fineout-Overholt et al., 2010, p. 48).
3. Will the results help me in caring for my patients?