Continued Potassium Supplementation Use Following Loop Diuretic Discontinuation in Older Adults

An Evaluation of a Prescribing Cascade Relic

Grace Hsin-Min Wang PharmD, MS; Earl J. Morris PharmD, MPH; Steven M. Smith PharmD, MPH; Jesper Hallas MD, DrMedSc; Scott M. Vouri PharmD, PhD


J Am Geriatr Soc. 2023;71(2):505-515. 

In This Article

Abstract and Introduction


Background: The use of a new medication (e.g., potassium supplementation) for managing a drug-induced adverse event (e.g., loop diuretic-induced hypokalemia) constitutes a prescribing cascade. However, loop diuretics are often stopped while potassium may be unnecessarily continued (i.e., relic). We aimed to quantify the occurrence of relics using older adults previously experiencing a loop diuretic-potassium prescribing cascade as an example.

Methods: We conducted a prescription sequence symmetry analysis using the population-based Medicare Fee-For-Service data (2011–2018) and partitioned the 150 days following potassium initiation by day to assess the daily treatment scenarios (i.e., loop diuretics alone, potassium alone, combination of loop diuretics and potassium, or neither). We calculated the proportion of patients developing the relic, proportion of person-days under potassium alone, the daily probability of the relic, and the proportion of patients filling potassium after loop diuretic discontinuation. We also identified the risk factors of the relic.

Results: We identified 284,369 loop diuretic initiators who were 8 times more likely to receive potassium supplementation simultaneously or after (i.e., the prescribing cascade), rather than before, loop diuretic initiation (aSR 8.0, 95% CI 7.9–8.2). Among the 66,451 loop diuretic initiators who subsequently (≤30 days) initiated potassium, 20,445 (30.8%) patients remained on potassium after loop diuretic discontinuation, and 9365 (14.1%) patients subsequently filled another potassium supplementation. Following loop diuretic initiation, 4.0% of person-days were for potassium alone, and daily probability of the relic was the highest after day 90 of loop diuretic initiation (5.6%). Older age, female sex, higher diuretic daily dose, and greater baseline comorbidities were risk factors for the relic, while patients having the same prescriber or pharmacy involved in the use of both medications were less likely to experience the relic.

Conclusions: Our findings suggest the need for clinicians to be aware of the potential of relic to avoid unnecessary drug use.


The use of a new medication for managing a drug-induced adverse event constitutes a prescribing cascade.[1] A recent review showed that at least 340 prescribing cascades have been described using the sequence symmetry analysis, including calcium channel blockers-loop diuretics,[2] gabapentinoids-loop diuretics,[3] cholinesterase inhibitors-anticholinergics.[4,5] Another commonly-observed prescribing cascade is the use of potassium supplementation following loop diuretic-induced hypokalemia,[6] which is intentional and appropriate in most cases,[7] and therefore is considered a standard clinical care.[8]

Providers or patients should discontinue loop diuretics if they are no longer needed[9,10] or are bothersome for the patient.[11] In general, discontinuation of loop diuretics should be accompanied by discontinuation of potassium supplementation. However, the occurrence of this phenomenon, to our knowledge, has not been described in previous literature. As such, we defined this phenomenon as a "prescribing cascade relic" ("relic" hereafter). In this study, we aimed to (1) evaluate the "loop diuretic-hypokalemia-potassium supplementation" prescribing cascade, and (2) quantify the presence and identify the risk factors of continued potassium supplementation use following loop diuretic discontinuation (i.e., relic) among older adults previously experiencing a loop diuretic-potassium supplementation prescribing cascade.