Improving the measurement of longitudinal change in renal function: automated detection of changes in laboratory creatinine assay.

INTRODUCTION: Renal function is reported using the estimates of glomerular filtration rate (eGFR). However, eGFR values are recorded without reference to the particular serum creatinine (SCr) assays used to derive them, and newer assays were introduced at different time points across the laboratories in the United Kingdom. These changes may cause systematic bias in eGFR reported in routinely collected data, even though laboratory-reported eGFR values have a correction factor applied. DESIGN: An algorithm to detect changes in SCr that in turn affect eGFR calculation method was developed. It compares the mapping of SCr values on to eGFR values across a time series of paired eGFR and SCr measurements. SETTING: Routinely collected primary care data from 20,000 people with the richest renal function data from the quality improvement in chronic kidney disease trial. RESULTS: The algorithm identified a change in eGFR calculation method in 114 (90%) of the 127 included practices. This change was identified in 4736 (23.7%) patient time series analysed. This change in calibration method was found to cause a significant step change in the reported eGFR values, producing a systematic bias. The eGFR values could not be recalibrated by applying the Modification of Diet in Renal Disease equation to the laboratory reported SCr values. CONCLUSIONS: This algorithm can identify laboratory changes in eGFR calculation methods and changes in SCr assay. Failure to account for these changes may misconstrue renal function changes over time. Researchers using routine eGFR data should account for these effects.

A simple clinical coding strategy to improve recording of child maltreatment concerns: an audit study.

BACKGROUND: Recording concerns about child maltreatment, including minor concerns, is recommended by the General Medical Council (GMC) and National Institute for Health and Clinical Excellence (NICE) but there is evidence of substantial under-recording. AIM: To determine whether a simple coding strategy improved recording of maltreatment-related concerns in electronic primary care records. DESIGN AND SETTING: Clinical audit of rates of maltreatment-related coding before January 2010-December 2011 and after January-December 2012 implementation of a simple coding strategy in 11 English family practices. The strategy included encouraging general practitioners to use, always and as a minimum, the Read code 'Child is cause for concern'. A total of 25,106 children aged 0-18 years were registered with these practices. We also undertook a qualitative service evaluation to investigate barriers to recording. METHOD: Outcomes were recording of 1) any maltreatment-related codes, 2) child protection proceedings and 3) child was a cause for concern. RESULTS: We found increased recording of any maltreatment-related code (rate ratio 1.4; 95% CI 1.1-1.6), child protection procedures (RR 1.4; 95% CI 1.1-1.6) and cause for concern (RR 2.5; 95% CI 1.8-3.4) after implementation of the coding strategy. Clinicians cited the simplicity of the coding strategy as the most important factor assisting implementation. CONCLUSION: This simple coding strategy improved clinician's recording of maltreatment-related concerns in a small sample of practices with some 'buy-in'. Further research should investigate how recording can best support the doctor-patient relationship. HOW THIS FITS IN: Recording concerns about child maltreatment, including minor concerns, is recommended by the General Medical Council (GMC) and National Institute for Health and Clinical Excellence (NICE), but there is evidence of substantial under-recording. We describe a simple clinical coding strategy that helped general practitioners to improve recording of maltreatment-related concerns. These improvements could improve case finding of children at risk and information sharing.

Serum phosphate as a risk factor for cardiovascular events in people with and without chronic kidney disease: a large community based cohort study.

BACKGROUND: Serum phosphate is a known risk factor for cardiovascular events and mortality in people with chronic kidney disease (CKD), however data on the association of these outcomes with serum phosphate in the general population are scarce. We investigate this relationship in people with and without CKD in a large community-based population. METHODS: Three groups from an adult cohort of the Quality Improvement in Chronic Kidney Disease (QICKD) cluster randomised trial (ISRCTN56023731) were followed over a period of 2.5 years: people with normal renal function (N = 24,184), people with CKD stages 1-2 (N = 20,356), and people with CKD stages 3-5 (N = 13,292). We used a multilevel logistic regression model to determine the association between serum phosphate, in these groups, and a composite outcome of all-cause mortality, cardiovascular events, and advanced coronary artery disease. We adjusted for known cardiovascular risk factors. FINDINGS: Higher phosphate levels were found to correlate with increased cardiovascular risk. In people with normal renal function and CKD stages 1-2, Phosphate levels between 1.25 and 1.50 mmol/l were associated with increased cardiovascular events; odds ratio (OR) 1.36 (95% CI 1.06-1.74; p = 0.016) in people with normal renal function and OR 1.40 (95% CI 1.09-1.81; p = 0.010) in people with CKD stages 1-2. Hypophosphatemia (<0.75 mmol/l) was associated with fewer cardiovascular events in people with normal renal function; OR 0.59 (95% CI 0.36-0.97; p = 0.049). In people with CKD stages 3-5, hyperphosphatemia (>1.50 mmol/l) was associated with increased cardiovascular risk; OR 2.34 (95% CI 1.64-3.32; p<0.001). Other phosphate ranges were not found to have a significant impact on cardiovascular events in people with CKD stages 3-5. CONCLUSIONS: Serum phosphate is associated with cardiovascular events in people with and without CKD. Further research is required to determine the mechanisms underlying these associations.