Table 2.
Case-crossover studies
| Windows(days) | Crude Effect | Adj. analysisa | N | Discordant pairs | ||
|---|---|---|---|---|---|---|
| Hazard period | Control period | ORMH (95% CI) | ORMH (95% CI) | With drug (all patients) | Hazard; control | |
| Potassium | ||||||
| Main analysis | 1–30 | 31–60 | 2.04 (1.24–3.36) ** | 1.70 (1.01–2.86) * | 118 (2185) | 47; 23 |
| Washout | 1–30 | 61–90 | 5.00 (2.54–9.86) *** | 3.60 (1.78–7.26) *** | 118 (2185) | 50; 10 |
| Multiple control windows | 1–30 | 31–60, 61–90, […], 151–180 | 3.54 (2.42–5.18) *** | 2.56 (1.73–3.79) *** | 118 (2185) | CLRb |
| NSAIDs | ||||||
| Main analysis | 1–30 | 31–60 | 1.80 (1.39–2.33) *** | 1.50 (1.14–1.97) ** | 543 (2185) | 160; 89 |
| Washout | 1–30 | 61–90 | 1.85 (1.41–2.41) *** | 1.64 (1.24–2.18) *** | 543 (2185) | 155; 84 |
| Multiple control windows | 1–30 | 31–60, 61–90, […], 151–180 | 1.60 (1.32–1.93) *** | 1.29 (1.06–1.56) * | 543 (2185) | CLRb |
| Amoxicillin/clavulanic acid | ||||||
| Main analysis | 1–15 | 16–30 | 3.25 (2.06–5.14) *** | 2.26 (1.41–3.62) *** | 318 (2185) | 78; 24 |
| Washout | 1–15 | 31–45 | 3.86 (2.39–6.23) *** | 2.41 (1.46–3.97) *** | 318 (2185) | 81; 21 |
| Multiple control windows | 1–15 | 16–30, 31–45, […], 166–180 | 3.22 (2.50–4.15) *** | 1.87 (1.43–2.44) *** | 318 (2185) | CLRb |
ORMH, Mantel-Haenszel odds ratio; 95% CI, 95% confidence interval for ORMH; Discordant pairs, patients with medication exposure in hazard period but not in control period or vice versa; N, number of patient with at least one prescription of the respective drug within 180 days, out of all patients
*p < 0.05, ** p < 0.01, ***p < 0.001
aConditional logistic regression models were adjusted for the number of outpatient physician visits per time window and prescription of high-ceiling diuretics (sulfonamides) simultaneously
bCLR = odds ratios were retrieved from conditional logistic regression analysis