ObjectiveUS can detect subclinical joint-inflammation in patients with clinically suspect arthralgia (CSA), which is valuable as predictor for RA development. In most research protocols both hands... Show moreObjectiveUS can detect subclinical joint-inflammation in patients with clinically suspect arthralgia (CSA), which is valuable as predictor for RA development. In most research protocols both hands and forefeet are scanned, but it is unclear if US of the forefeet has additional value for predicting RA, especially since synovial hypertrophy in MTP-joints of healthy individuals is also common. To explore the possibility to omit scanning of the forefeet we determined if US of the forefeet is of additional predictive value for RA-development in CSA patients.MethodsCSA patients of two independent cohorts underwent US of the hands and forefeet. We analysed the association between RA-development and US-positivity for the full US-protocol, the full US-protocol with correction for gray scale (GS)-findings in the forefeet of healthy and the protocol without forefeet.ResultsIn total, 298 CSA patients were studied. In patients with a positive US, subclinical joint-inflammation was mostly present in the hands (90–86%). Only 10–14% of patients had subclinical joint-inflammation solely in the forefeet. US-positivity was associated with inflammatory arthritis development in both cohorts, with HRs 2.6 (95% CI 0.9–7.5) and 3.1 (95% CI 1.5–6.4) for the full protocol, 3.1 (95% CI 1.3–7.7) and 2.7 (95% CI 1.3–5.4) for the full US-protocol with correction, and 3.1 (95% CI 1.4–6.9) and 2.8 (95% CI 1.4–5.6) without the forefeet. AUROCs were equal across both cohorts.ConclusionThe forefeet can be omitted when US is used for the prediction of RA-development in CSA patients. This is due to the finding that subclinical joint-inflammation in the forefeet without concomitant inflammation in the hands is infrequent. Show less
Observational pharmacoepidemiological studies using routinely collected healthcare data are increasingly being used in the field of nephrology to answer questions on the effectiveness and safety of... Show moreObservational pharmacoepidemiological studies using routinely collected healthcare data are increasingly being used in the field of nephrology to answer questions on the effectiveness and safety of medications. This review discusses a number of biases that may arise in such studies and proposes solutions to minimize them during the design or statistical analysis phase. We first describe designs to handle confounding by indication (e.g. active comparator design) and methods to investigate the influence of unmeasured confounding, such as the E-value, the use of negative control outcomes and control cohorts. We next discuss prevalent user and immortal time biases in pharmacoepidemiology research and how these can be prevented by focussing on incident users and applying either landmarking, using a time-varying exposure, or the cloning, censoring and weighting method. Lastly, we briefly discuss the common issues with missing data and misclassification bias. When these biases are properly accounted for, pharmacoepidemiological observational studies can provide valuable information for clinical practice. Show less
Cnossen, M.C.; Essen, T.A. van; Ceyisakar, I.E.; Polinder, S.; Andriessen, T.M.; Naalt, J. van der; ... ; Lingsma, H.F. 2018
