Metabolic acidosis is undertreated and underdiagnosed: a retrospective cohort study

BACKGROUND: Guidelines recommend treatment of metabolic acidosis (MA) in patients with chronic kidney disease (CKD), but the diagnosis and treatment rates in real-world settings are unknown. We investigated the frequency of MA treatment and diagnosis in patients with CKD. METHODS: In this retrospective cohort study, we examined administrative health data from two US databases [Optum's de-identified Integrated Claims + Clinical Electronic Health Record Database (US EMR cohort; 1 January 2007 to 30 June 2019) and Symphony Health Solutions IDV® (US claims cohort; 1 May 2016 to 30 April 2019)] and population-level databases from Manitoba, Canada (1 April 2006 to 31 March 2018). Patients who met laboratory criteria indicative of CKD and chronic MA were included: two consecutive estimated glomerular filtration results <60 mL/min/1.73 m2 and two serum bicarbonate results 12 to <22 mEq/L over 28-365 days. Outcomes included treatment of MA (defined as a prescription for oral sodium bicarbonate) and a diagnosis of MA (defined using administrative records). Outcomes were assessed over a 3-year period (1 year pre-index, 2 years post-index). RESULTS: A total of 96 184 patients were included: US EMR, 6179; Manitoba, 3223; US Claims, 86 782. Sodium bicarbonate treatment was prescribed for 17.6%, 8.7% and 15.3% of patients, and a diagnosis was found for 44.7%, 20.9% and 20.9% of patients, for the US EMR, Manitoba and US Claims cohorts, respectively. CONCLUSIONS: This analysis of 96 184 patients with laboratory-confirmed MA from three independent cohorts of patients with CKD and MA highlights an important diagnosis and treatment gap for this disease-modifying complication.