Page 164 - Exploring the Potential of Self-Monitoring Kidney Function After Transplantation - Céline van Lint

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Chapter 7
There are, however, two reasons why the percentage of similar trends found in the RCT could actually even be an underestimation of the real similarity between home-based and laboratory-based creatinine measurements. First, level of agreement was based on a comparison between laboratory- based creatinine trends and self-measured values that were registered in the SMSS, not on values that were stored in the creatinine device. As in about 10% of registrations the registered value did not correspond to the actually measured one, it is expected that level of correspondence between laboratory-based and home-based creatinine trends will be higher if values from the devices’ memory are used. Second, level of agreement between self-measured and laboratory-based creatinine trends could have been higher if the protocol was followed more strictly. When determining the protocol, we assumed that every other face to face visit would be replaced by a telephonic consult resulting in a lower frequency of laboratory analyses. We used a 1:7 ratio for determining the required measurement frequency, meaning that ideally patients performed seven creatinine measurements to replace one outpatient visit with laboratory assessment. As less outpatient visits were replaced by a telephonic consult than expected (causing the frequency of laboratory analysis to be higher than expected), the number of self-monitored values in between two laboratory assessments was lower. It is possible that the correspondence between home- and laboratory-based creatinine trends would have been even better if more home measurements in between two laboratory assessments would have been available, because a higher number of measurements results in a more reliable trend.
Non-inferiority to regular care
To investigate whether self-monitoring kidney function supported by a SMSS can indeed lead to a reduction in number of outpatient visits in the first year post-transplantation without compromising on quality of care, a randomized controlled trial was performed (described in chapter 5). Self- monitoring led to a significant decrease in number of outpatient visits and total number of reimbursable minutes spent per patient. This achievement was made without compromising on quality of care, indicated by the absence of differences between intervention and control patients regarding kidney function, blood pressure, quality of life and general satisfaction at one-year follow-up. Five self- monitoring patients experienced a rejection episode during their participation in the RCT. In three of these cases, the emerging rejection was detected earlier (i.e. in between two consults) due to the creatinine measurements performed at home, while none appeared to be missed.
The actual difference in number of face-to-face visits between the intervention and control group was, however, smaller than expected. Following our protocol exactly (i.e. replacing half of the face to face visits by a telephonic one from week eight after transplantation onwards), the expected difference in