The association between urine protein:creatinine ratio, end-stage renal disease and healthcare resource use in patients with lupus nephritis

Date of Approval
Application Number
Technical Summary

The development of ESRD in LN patients significantly increases morbidity, mortality and leads to enormous healthcare cost. We wish to conduct a retrospective cohort study to assess the use of urine protein: serum creatinine ratio (uPCR) in informing about ESRD occurrence in lupus nephritis. The primary objective is to evaluate the correlation between uPCR measurement and end-stage renal disease in patients with lupus nephritis. Secondary objectives are (a) to describe the demographics and clinical characteristics of patients with lupus nephritis, (b) to determine their healthcare resource use and cost. Adult patients with lupus nephritis will be identified in CPRD-HES linkage between 1st of April 2009 and 30th of June 2019. First urine protein:serum creatinine ratio (uPCR) following study start will be identified as index date (baseline measure) and ESRD-outcome will be identified during follow up. A two-stage analysis will be applied: first risk matrix association between the absolute value of uPCR at baseline and ESRD will be examined using multivariate logistic regression. uPCR will be included in the model as an ordered categorical variable and adjustments will be made for confounding variables. Secondly, the relationship between changes in uPCR and ESRD will be assessed using cox-proportional hazard regression with linear splines with knots at significant uPCR levels and adjusting for covariates. Annual average rates of healthcare resource use (as GP-consultations, out-patient appointments, A&E attendances, inpatient admissions, inpatient length of stay) and tariff admission cost will be estimated during follow up. Descriptive statistics will be used to capture sociodemographic and clinical characteristics of patients.

Health Outcomes to be Measured

Demographics (mean and median age on inclusion, gender, deprivation quantiles, and ethnicity categories). Clinical characteristics (Charlson comorbidities, Charlson comorbid index score, prescriptions medication for Lupus nephritis; corticosteroid, other-steroids, calcineurin inhibitors, mycophenolate, other immunomodulators, cyclophosphamide, rituximab, smoking status and body-mass index). Mean and median follow up time. Healthcare resource outcomes (mean GP-consultations, total appointments and cost in primary care, outpatients appointments, A&E attendances, inpatient admissions, inpatient length of stay, inpatients HRG tariffs cost per patient per year) Clinical outcomes; diagnosis of end-stage renal disease post index-date and during follow up and survival time during follow up.


Jay Were - Chief Investigator - Health iQ
Muna Adan - Corresponding Applicant - Health iQ
Archie Farrer - Collaborator - Health iQ
Boglarka Kovacs - Collaborator - Health iQ
Caoimhe Rice - Collaborator - Health iQ
Gulsah Akin Unal - Collaborator - Health iQ
Judith Ruzangi - Collaborator - Health iQ
Mico Hamlyn - Collaborator - Health iQ


HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation