To the Editor:
Spironolactone is increasingly prescribed for female patients with acne.1 While potassium monitoring may be of low value in young, healthy females, monitoring is still recommended for those with risk factors such as age, comorbidities, or concurrent medications.2–4 In addition, given limited trial data evaluating the safety of spironolactone for acne, some patients and clinicans may prefer monitoring as part of shared decision making. In routine clinical practice, potassium monitoring is considered for over a third of patients treated with spironolactone.3
For those undergoing potassium monitoring, spironolactone prescribing information recommends this is done within 1 week of starting the medication, and guidelines for use in heart failure and hypertension recommend monitoring within 1 to 4 weeks. However, little is known regarding whether potassium monitoring is performed within this recommended timeframe.
This cohort study was performed using the Truven Health MarketScan Commercial Claims Database from January 1, 2017, to December 31, 2020. Inclusion criteria were (1) female; (2) age ≥12 years-old; (3) ≥1 encounter with an ICD-10 code for acne5; (4) prescription for spironolactone after an encounter for acne, with beginning of treatment defined as the index date; (5) spironolactone course duration ≥90 days; and (6) continuous enrollment ≥180 days prior to and after the index date.
Potassium lab claims were identified by Current Procedural Terminology codes (84132, 80047, 80048, 80051, 80053). Pretreatment potassium testing was defined as labs obtained within 180 days prior to the index date (start of treatment). Descriptive statistics are presented regarding timing of potassium monitoring relative to the index date. This study followed STROBE reporting guidelines and was exempt from institutional review board review given use of deidentified data. Statistical analyses were performed using Python 3.8.2.
Among 32,234 patients treated with spironolactone, the mean (SD) age at the start of treatment was 31.3 (11.6) years old (Table I). Among those with potassium monitoring, 5.5% had potassium checked within 7 days, 10.7% within 14 days, 23.7% within 30 days, 55.9% within 90 days, and 73.0% within 180 days. Similar patterns were observed across age groups, including those ≥45 years-old (Table I). Overall, 31.1% had potassium monitoring during therapy, including 22.4%, 27.7%, 33.7%, and 43.3% who were 12–19, 20–29, 30–44, and ≥45 years-old. There were modest decreases in the frequency of potassium monitoring across all age groups during the study period (Fig 1).
Table I.
Characteristics of serum potassium monitoring in females on spironolactone for acne
| Variable | All (n = 32,234) | 12–19 years (n = 5355) | 20–29 years (n = 11,872) | 30–44 years (n = 10,215) | ≥45 years (n = 4792) |
|---|---|---|---|---|---|
|
| |||||
| Age, mean (SD), y | 31.3 (11.6) | 17.0 (1.4) | 24.3 (2.7) | 37.1 (4.3) | 51.5 (5.1) |
| Spironolactone course duration, mean (SD), d | 269.7 (200.4) | 257.2 (177.8) | 257.7 (179.8) | 276.8 (212.4) | 297.9 (236.9) |
| Females with pretreatment serum potassium measurement, % | 35.7% | 22.3% | 30.2% | 40.1% | 54.7% |
| Females with serum potassium measurement during spironolactone course, % | 31.1% | 22.4% | 27.7% | 33.7% | 43.3% |
| Females with ≥2 serum potassium measurements during spironolactone course, % | 10.1% | 6.0% | 8.0% | 11.4% | 17.2% |
| Time to first serum potassium measurement after starting spironolactone, mean (SD), d | 118 (130) | 119 (126) | 117 (124) | 120 (137) | 114 (131) |
| Time to second serum potassium measurement after the first measurement, mean (SD), d | 113 (128) | 102 (117) | 105 (124) | 119 (133) | 119 (130) |
| Females with a serum potassium measurement within 7 days after starting spironolactone*, % | 5.5% | 5.2% | 5.1% | 5.3% | 6.8% |
| Females with a serum potassium measurement within 14 days after starting spironolactone*, % | 10.7% | 9.3% | 9.9% | 10.4% | 13.4% |
| Females with a serum potassium measurement within 30 days after starting spironolactone*, % | 23.7% | 21.6% | 22.3% | 24.0% | 26.6% |
| Females with a serum potassium measurement within 90 days after starting spironolactone*, % | 55.9% | 54.5% | 54.8% | 56.6% | 57.1% |
| Females with a serum potassium measurement within 180 days after starting spironolactone*, % | 73.0% | 69.5% | 72.8% | 73.3% | 74.6% |
The number of patients with potassium labs within N days of the index date was standardized to the number of patients with potassium monitoring and course duration ≥ N days.
Among those with serum potassium measurement during spironolactone course.
Fig 1.
Temporal trends in frequency of potassium level monitoring among females treated for acne with spironolactone. The number of patients with potassium labs during therapy each year was standardized to the number of patients on spironolactone for acne during each year.
Our results highlight that among those with potassium monitoring, this testing is rarely performed within a few weeks of starting spironolactone as recommended. This represents an important practice gap and opportunity to improve quality of care, since early detection of hyperkalemia can decrease the risk of complications. Similar to prior studies, we also identified that potassium monitoring is a common practice, even among younger populations. While the modest decrease in the use of potassium monitoring over the study period is an encouraging trend, there may be further opportunities to optimize use of lab monitoring in this population.
Study limitations include that the reason potassium labs were obtained could not be accounted for, such as dose increases, symptomology, or indications unrelated to spironolactone; however, the latter was mitigated by considering labs only during therapy. This study demonstrates the importance of education and the need to address timing of potassium monitoring in dermatology clinical practice guidelines for treatment of acne with spironolactone.
Footnotes
Conflicts of interest
Dr Barbieri reported personal fees from Dexcel Pharma for consulting outside the submitted work. Drs Lai and Zaenglein have no conflicts of interest to declare.
Patient consent: Not applicable.
IRB approval status: Exempt.
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