Table 3
Changes in Test Order Rates Associated With Decision Support Interventions
| Orders* | Instances* | |||
| Tests | Value | p Value† | Value | p Value† |
| Magnesium | ||||
| Mean weekly tests during baseline period | 234 | — | 539 | — |
| Baseline trend in weekly tests | 0.1 | 0.845 | −0.5 | 0.163 |
| Weekly test rate after the first intervention‡ | 219 | 0.640 | 378 | 0.001 |
| Weekly test rate after the second intervention | 485 | <0.001 | 491 | 0.022 |
| Trend change in the weekly test rate after the second intervention | 0.6 | 0.315 | 1.5 | 0.050 |
| Weekly test rate after the third intervention | 230 | <0.001 | 277 | <0.001 |
| Trend change in the weekly test rate related the third intervention | 0.9 | 0.076 | 1.6 | 0.007 |
| Mean weekly test rate at the end of study period | 320 | — | 379 | — |
| Calcium | ||||
| Mean weekly tests during baseline period | 200 | — | 400 | — |
| Baseline trend in weekly tests | 0.1 | 0.924 | −0.5 | 0.361 |
| Weekly test rate after the first intervention‡ | 190 | 0.822 | 336 | 0.643 |
| Weekly test rate after the second intervention | 368 | 0.113 | 452 | 0.541 |
| Trend change in the weekly test rate after the second intervention | 2.5 | 0.012 | 3.6 | 0.003 |
| Weekly test rate after the third intervention | 462 | 0.045 | 621 | 0.001 |
| Trend change in the weekly test rate related the third intervention | 7.6 | < 0.001 | 8.0 | < 0.001 |
| Mean weekly test rate at the end of study period | 1259 | — | 1417 | — |
| Phosphorus | ||||
| Mean weekly tests during baseline period | 108 | — | 282 | — |
| Baseline trend in weekly tests | 0.1 | 0.662 | 0.1 | 0.777 |
| Weekly test rate after the first intervention‡ | 107 | 0.823 | 227 | 0.056 |
| Weekly test rate after the second intervention | 292 | < 0.001 | 313 | 0.011 |
| Trend change in the weekly test rate after the second intervention | 1.1 | 0.008 | 1.5 | 0.015 |
| Weekly test rate after the third intervention | 229 | 0.008 | 289 | 0.189 |
| Trend change in the weekly test rate related the third intervention | 0.7 | 0.054 | 0.8 | 0.057 |
| Mean weekly test rate at the end of study period | 309 | — | 363 | — |
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↵* All outcomes are corrected for changes in weekly admission rates.
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↵† p Values for “weekly test rate” tests the hypothesis that the current rate is the same as the preceding rate. p Values for “trend change” tests the hypothesis that the current trend is equal to zero.
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↵‡ Trends during the period when the first tool was implemented could not be tested due to inadequate sample.
