Evaluation of administrative case definitions for chronic kidney disease in children.

INTRODUCTION: Administrative data is increasingly used for chronic disease surveillance; however, its validity to define cases of chronic kidney disease (CKD) in children is unknown. We sought to evaluate the performance of case definitions for CKD in children. METHODS: We utilized population-based administrative data from the Manitoba Center for Health Policy to evaluate the validity of algorithms based on a combination of hospital claims, outpatient physician visits, and pharmaceutical use over 1-3 years in children <18 years of age. Algorithms were compared with a laboratory-based definition (estimated glomerular filtration rate < 90 ml/min/1.73 m2 and/or presence of proteinuria). RESULTS: All algorithms evaluated had very low sensitivity (0.20-0.39) and moderate positive predictive value (0.52-0.68). Algorithms had excellent specificity (0.98-0.99) and negative predictive value (0.96-0.97). Receiver operating characteristic (ROC) curves indicate fair accuracy (0.60-0.68). Sensitivity improved with increasing years of data. One or more physician claims and one or more prescriptions over 3 years had the highest sensitivity and ROC. CONCLUSIONS: The sensitivity of administrative data algorithms for CKD is unacceptably low for a screening test. Specificity is excellent; therefore, children without CKD are correctly identified. Alternate data sources are required for population-based surveillance of this important chronic disease.

Prevalence, socio-demographic characteristics, and comorbid health conditions in pre-dialysis chronic kidney disease: results from the Manitoba chronic kidney disease cohort.

BACKGROUND: Chronic Kidney Disease (CKD) is common and its prevalence has increased steadily over several decades. Monitoring of rates and severity of CKD across populations is critical for policy development and resource planning. Administrative health data alone has insufficient sensitivity for this purpose, therefore utilizing population level laboratory data and novel methodology is required for population-based surveillance. The aims of this study include a) develop the Manitoba CKD Cohort, b) estimate CKD prevalence, c) identify individuals at high risk of progression to kidney failure and d) determine rates of comorbid health conditions. METHODS: Administrative health and laboratory data from April 1996 to March 2012 were linked from the data repository at the Manitoba Centre for Health Policy. Prevalence was estimated using three methods: a) all CKD cases in administrative and laboratory databases; b) all CKD cases captured only through the laboratory data; c) and the capture-recapture method. Patients were stratified by risk by estimated Glomerular Filtration Rate (eGFR) and albuminuria based on Kidney Disease Improving Global Outcomes (KDIGO) criteria. For comorbid health conditions, the counts were modelled using a Generalized Linear Model (GLM). RESULTS: The Manitoba CKD Cohort consisted of 55,876 people with CKD. Of these, 18,342 were identified using administrative health data, 27,393 with laboratory data, and 10,141 people were identified in both databases. The CKD prevalence was 5.6% using the standard definition, 10.6% using only people captured by the laboratory data and 10.6% using the capture-recapture method. Of the identified cases, 46% were at high risk of progression to end-stage kidney disease (ESKD), 41% were at low risk and 13% were not classified, due to unavailable laboratory data. High risk cases had a higher burden of comorbid conditions. CONCLUSION: This study reports a novel methodology for population based CKD surveillance utilizing a combination of administrative health and laboratory data. High rates of CKD at risk of progression to ESKD have been identified with this approach. Given the high rates of comorbidity and associated healthcare costs, these data can be used to develop a targeted and comprehensive public health surveillance strategy that encompass a range of interrelated chronic diseases.

Do primary care physicians coordinate ambulatory care for chronic disease patients in Canada?

BACKGROUND: Adults with chronic disease are the most frequent users of the primary healthcare system. In Manitoba, patients are allowed to seek ambulatory (outpatient) care from the provider of their choosing (primary care physician or specialist), with referrals to specialists preferred but not always required. Some patients receive their routine care from specialists. We conducted this study to determine the patterns by which adults with chronic disease access ambulatory care as a prelude to exploring the impact these patterns may have on the quality of care received. METHODS: Physician claims for all visits between 2007/8-2009/10 were extracted from the Data Repository at the Manitoba Centre for Health Policy. Patients included in the analysis made at least four ambulatory visits to a primary care physician or specialist within the study period, and met the definition criteria for at least one of six chronic diseases: diabetes mellitus; congestive heart failure; mood disorders; ischemic heart disease; total respiratory morbidity; and/or hypertension. Patients were "assigned" to the physician they visited most regularly. Physician visit patterns were assessed by dividing visits into nine visit types based on the type of physician patients visited (assigned primary care physician, other primary care physician, or specialist) and whether or not they received a referral. RESULTS: 347,606 patients with 7,662,411 physician visits were included in the analysis. Most visits were to the patients' assigned primary care physician. About 50% of the visits to specialists were by referral from the assigned primary care physician. However, 26-29% of all visits to a primary care physician were not to the assigned primary care physician, and non-assigned physicians were more likely to refer patients to specialists than assigned primary care physicians. CONCLUSION: The findings suggest that the current primary care system in Manitoba may not adequately support coordination of ambulatory care. Ambulatory visits to a primary care provider who is not the patient's regular provider may represent a lost opportunity for coordination and continuity of care, and may affect the quality of care patients receive. Primary care renewal initiatives in this province should address this challenge to service provision.