Table 3.
Quantified effects of hypothetical unmeasured and/or unknown confounders in cohort of people with type 1 diabetes treated with insulin pump therapy or multiple daily injections (MDIs). Hypothetical binary confounder was assigned hazard ratio of 1.3 or 1.4 for all outcomes listed below. Hazard ratios associated with insulin pump treatment were given different prevalences of this confounder between two groups. Figures are hazard ratios (95% confidence intervals) after adjustment for binary confounder
| Confounder with hazard ratio 1.3 | Confounder with hazard ratio 1.4 | ||||
|---|---|---|---|---|---|
| Prevalence of confounder in pump group | Prevalence of confounder in pump group | ||||
| 0.0 | 0.2 | 0.0 | 0.2 | ||
| Fatal/non-fatal coronary heart disease | |||||
| Prevalence of confounder in MDI group: | |||||
| 0.0 | 0.81 (0.66 to 1.01) | 0.76 (0.62 to 0.95) | 0.81 (0.66 to 1.01) | 0.75 (0.61 to 0.94) | |
| 0.2 | 0.86 (0.70 to 1.07) | 0.81 (0.66 to 1.01) | 0.87 (0.71 to 1.09) | 0.81 (0.66 to 1.01) | |
| Fatal/non-fatal cardiovascular disease | |||||
| Prevalence of confounder in MDI group: | |||||
| 0.0 | 0.88 (0.73 to 1.06) | 0.83 (0.69 to 1.00) | 0.88 (0.73 to 1.06) | 0.81 (0.67 to 0.98) | |
| 0.2 | 0.93 (0.77 to 1.12) | 0.88 (0.73 to 1.06) | 0.95 (0.79 to 1.14) | 0.88 (0.73 to 1.06) | |
| Fatal cardiovascular disease | |||||
| Prevalence of confounder in MDI group: | |||||
| 0.0 | 0.58 (0.40 to 0.85) | 0.55 (0.38 to 0.80) | 0.58 (0.40 to 0.85) | 0.54 (0.37 to 0.79) | |
| 0.2 | 0.61 (0.42 to 0.90) | 0.58 (0.40 to 0.85) | 0.63 (0.43 to 0.92) | 0.58 (0.40 to 0.85) | |
| 0.4 | 0.65 (0.45 to 0.95) | 0.61 (0.42 to 0.90) | 0.67 (0.46 to 0.98) | 0.63 (0.43 to 0.92) | |
| 0.6 | 0.68 (0.47 to 1.00) | 0.65 (0.45 to 0.95) | 0.72 (0.50 to 1.05) | 0.67 (0.46 to 0.98) | |
| 0.8 | 0.72 (0.50 to 1.05) | 0.68 (0.47 to 1.00) | 0.77 (0.53 to 1.12) | 0.72 (0.50 to 1.05) | |
| Total mortality | |||||
| Prevalence of confounder in MDI group: | |||||
| 0.0 | 0.73 (0.58 to 0.92) | 0.69 (0.55 to 0.87) | 0.73 (0.58 to 0.92) | 0.68 (0.54 to 0.85) | |
| 0.2 | 0.77 (0.61 to 0.97) | 0.73 (0.58 to 0.92) | 0.79 (0.63 to 0.99) | 0.73 (0.58 to 0.92) | |
| 0.4 | 0.82 (0.65 to 1.03) | 0.77 (0.61 to 0.97) | 0.85 (0.67 to 1.07) | 0.79 (0.63 to 0.99) | |
| 0.6 | 0.86 (0.68 to 1.08) | 0.82 (0.65 to 1.03) | 0.90 (0.72 to 1.14) | 0.85 (0.67 to 1.07) | |