Table 3 Assessment of bias
Domain | From the study | Review authors’ judgement |
|---|---|---|
Giltin and Corcoran 1993[26] | ||
Selection bias. | “randomly assigned to either attention control group who received home-making services or a treatment group” [26 p14] No data presented on the control group characteristics | Method of allocation not specified. No comment |
Performance bias (blinding of participants and personnel) | Participants aware of receiving OT or home making service. OT aware they were providing the intervention. | Risk of bias |
Detection bias (blinding of outcome assessment). | OT providing the intervention also provided the assessment of reported outcomes (care giver acceptance of solutions and elimination of ineffective care giver approaches). | Risk of bias |
Attrition bias (incomplete outcome data) | No attrition from the study reported Data only provided for the intervention group on | Risk of bias |
Reporting bias. | Reporting only on the intervention group. | Risk of bias |
Jirovec and Templin 2001[27] | ||
Selection bias. | “Using a table of random numbers, volunteers were randomly assigned to either intervention or control group” [27 p2]. | Low risk |
Performance bias (blinding of participants and personnel) | Participants aware of receiving intervention or in control group. Personnel aware of those in the intervention or control group | Risk of bias |
Detection bias (blinding of outcome assessment). | “The same person collected data from the intervention participants and the control group data collectors were not involved in the intervention”p5 | Risk of bias |
Attrition bias (incomplete outcome data). | Attrition rate, 37%, and reasons reported. “The loss of participants between the groups was not significantly different” [27 p5]. Three of four study measures reported. The implementation of IST by carers was not reported. | Low risk Risk of bias |
Reporting bias. | The intervention arm was assigned into two groups, those that received bi-monthly visits and those that received a visit at 6 months. The data from these two arms were combined as the 6-month outcomes for percentage of time incontinent were “not significantly different” [27 p2] but not presented. | Risk of bias |
Other points | The paper reports that this is a significant decrease in the experimental group using the non-parametric sign test (Z= −1.83, p<.05) [27 p 5]. As these figures appeared inconsistent we re-ran the sign test using the reported data which gave Z=−1.81, p=0.07 which is borderline but not significant. We re-ran the data on another version of the sign test, the exact binomial which gave a value of p=0.09 i.e. still not statistically significant between the groups. | |
Endberg et al. 2002[28] | ||
Selection bias. | “Randomly assigned with use of a computerised minimisation algorithm” ( 28 p255) “Despite randomisation, the control group tended to have more severe incontinence than the treatment group” [28p259] | Low risk of bias |
Performance bias (blinding of participants and personnel) | Participants aware of receiving intervention or in control group. Personnel aware of those in the intervention or control group | Risk of bias |
Detection bias (blinding of outcome assessment). | “The 2 study NPs collected a comprehensive continence and medical history for the subject and caregiver” [28 p254] and provided the intervention and attention control.. “at the end of the treatment the subjects were reassessed” [28 p256] | Risk of bias |
Attrition bias (incomplete outcome data). | Three of 9 subjects randomly assigned to the treatment group dropped out or were excluded”[28 p260] All outcomes and measures reported | Low risk of bias |
Reporting bias. | All outcomes and measures reported | Low risk |