Abstract Background Hyperkalemia (HK) can affect health outcomes and quality of life, as it is referred to as a potentially life-threatening condition caused by an increased serum potassium concentration in the blood. Patients suffering from heart failure or chronic kidney diseases are at a higher risk of HK, which can further be amplified by the treatment received. To date, data on HK prevalence is lacking for Germany and the aims of this study were to assess HK and compare health-relevant outcomes and healthcare costs between HK patients and non-HK patients. Methods The InGef research database containing healthcare claims of over 4 million individuals in Germany was utilized for this retrospective, matched cohort analysis. Patients with non-acute outpatient treated and a subgroup of patients with chronic HK, were identified in 2015 with an individual 1 year pre- and post-index period, taking the first observable HK diagnosis/treatment in 2015 into account as the index event. To identify non-acute outpatient treated HK patients, at least two ICD-10-GM diagnosis codes E87.5 “Hyperkalemia” and/or prescriptions of polystyrene sulfonate were required. Chronic HK patients had additional diagnoses and/or prescriptions in all quarters following the first observable HK diagnosis. Patients without HK were matched 1:1 to the respective HK cohorts. Results In the year 2015, 3333 patients with non-acute outpatient treated HK were identified of which 1693 were patients with chronic HK. After matching, 3191 and 1664 HK patients and controls were available for analysis. A significantly higher number of hospitalizations was observed for both HK cohorts in comparison to their matched controls. Dialysis initiation as well as the healthcare costs were higher for both HK cohorts when compared to their matched counterparts. Conclusions The disease burden was higher for patients with HK, based on a higher proportion of patients with dialysis initiation and higher healthcare costs.