Table 2 Statistical Analysis Plan
Research Question | Outcomes and Measures | Participant Group(s) | Time Point | Hypotheses | Method of Analysis |
|---|---|---|---|---|---|
1. What is the difference in HbA1C levels between communities implementing CHAP-P and those not implementing CHAP-P? | • Mean difference in HbA1c (A1C Now+ point-of-care device) | Community survey participants | T0, T6 | Mean HbA1c level will have a greater decrease in intervention communities over control communities | Independent samples t-test (intervention vs control), One-way ANOVA (subgroup analysis), Generalized estimating equations (adjust for clustering effect) |
2. What is the difference in modifiable lifestyle risk factors between communities implementing CHAP-P and those not implementing CHAP-P? | • Physical activity (IPAQ) • Medication compliance (self-report, survey question) • Blood pressure (BP; WatchBP Office Target device) • Risk factors for diabetes (FINDRISC) • Risk Behaviours for Diabetes / Cardiovascular Issues (activity, diet, smoking, alcohol, stress; self-report, measured with elements of the Health Awareness and Behaviour Tool [HABiT]) • Knowledge about Diabetes and Hypertension (self-report; measured with elements of the HABiT) • Perceived Concern and Understanding of Risk (self-report; measured with elements of the HABiT) • Confidence in Behaviour Change (self-report; measured with elements of the HABiT) | Community survey participants (all outcomes) CHAP-P session participants (change in BP over time; diabetes risk score) | Survey T0, T6 Session BP: each session Diabetes risk score: T0, T6 | In intervention versus control communities, physical activity, medication compliance, knowledge, perceived concern and understanding of risk, and confidence in behaviour change will have more of an increase, blood pressure, diabetes risk score, and risk behaviours will have more of a decrease In CHAP-P session participants, blood pressure will decrease with more length of time involved in the program; diabetes risk score will decrease pre to post. | Independent samples t-test (intervention vs control), One-way ANOVA (subgroup analysis), Generalized estimating equations (adjust for clustering effect), Hierarchical linear modelling (BP over time) |
3. What is the difference in diabetes-specific outcomes between communities implementing CHAP-P and those not implementing CHAP-P?: (a) screening rates for diabetes, (i.e., rates of newly diagnosed cases of type 2 diabetes), (b) initiating medication treatment for diabetes management, and (c) hospital admission rates and mortality due to diabetes (and its complications), hypertension, myocardial infarction, stroke, and congestive heart failure? (d) self-reported health utilization and access | • a. N community residents newly diagnosed with diabetes (Rural Health Unit databases) • b. N community residents newly initiating medication treatment • c. Hospital admission rates due to diabetes and diabetes-related conditions, hypertension, MI, stroke, CHF (central Department of Health database) • d. Mortality rates due to diabetes and diabetes-related conditions, hypertension, MI, stroke, CHF based on ICD-10 codes (Regional Field Health Surveillance Information Systems) • e. Availability of health care services in community and whether there is a place they go when sick or need health advice (2 items; self-report) | a., b., c., d. N/A – administrative records representing intervention and control communities e. Community survey participants | a., b. T6 (for 6 months of program) c., d. T−12, T12 (for 12 months before & after program, divided by mid-year population estimates) e. T0, T6 | Intervention over control communities will have more residents newly diagnosed with diabetes, more residents newly initiating medication treatment for diabetes, a lower hospital admission rate due to diabetes and related conditions, and a lower mortality rate due to diabetes and related conditions | Generalized estimating equations (linear and Poisson Model, adjust for clustering effect) |
4. What is the cost-effectiveness and cost-utility of CHAP-P compared to usual care? | • Program cost (actual) • Healthcare resource utilization costs (self-report, survey) • Percentage reduction in HbA1c (A1C Now+ point-of-care device) • Quality of life (EQ-5D-5 L) • Quality-Adjusted Life Years (QALYs) (calculated from EQ-5D-5 L) | Community survey participants (healthcare resource utilization, HbA1c, quality-of-life) | T0, T6 | Not appropriate for this type of outcome | Cost-effectiveness: percentage decrease in HbA1c Cost-utility: cost per QALY (based on local EQ-5D-5 L) |
(Implementation Outcomes) | • Community process evaluation – interviews and focus groups, monthly community reports, observational fidelity checklists | Interview and focus group participants (BHWs, CHAP-P session participants, LLO staff) | T6 | Not appropriate for this type of outcome | Thematic analysis |