Facility variation and predictors of serum potassium monitoring after initiation of a mineralocorticoid receptor antagonist in patients with heart failure

A real-world cohort study on the quality of potassium and creatinine monitoring during initiation of mineralocorticoid receptor antagonists in patients with heart failure

Aims

Clinical heart failure (HF) guidelines recommend monitoring of creatinine and potassium throughout the initial weeks of mineralocorticoid receptor antagonists (MRAs) therapy. We here assessed the extent to which this occurs in our health care.

Methods and results

Observational study in 2007-2010 HF patients starting MRA therapy in Stockholm, Sweden. Outcomes included potassium and creatinine laboratory testing before MRA initiation and in the early (Days 1-10) and extended (Days 11-90) post-initiation periods. Exclusion criteria considered death/hospitalization within 90 days, and lack of a second MRA dispense. Of 4036 HF patients starting on MRA, 45% were initiated from a hospital, 24% from a primary care centre, and 30% from other private centres. Overall, 89% underwent pre-initiation testing, being more common among hospital (97%) than for primary care (74%) initiations. Only 24% were adequately monitored in all three recommended intervals, being again more frequent following hospital (33%) than private (21%) or primary care (17%) initiations. In multivariable analyses, adequate monitoring was more likely for hospital [odds ratio (OR) 2.85, 95% confidence interval (95% CI) 2.34-3.56] initiations, and for patients with chronic kidney disease (OR 1.79, 95% CI 1.30-2.43) and concomitant use of angiotensin-converting enzyme (OR 1.27, 95% CI 1.05-1.52), angiotensin receptor blockers (OR 1.19, 95% CI 1.01-1.40) or beta-blockers (OR 1.65, 95% CI 1.22-2.26). Age, sex, and prescribing centre explained a small portion of adequate monitoring (c-statistic 0.63). Addition of comorbidities and medications improved prediction marginally (c-statistic 0.65).

Conclusion

Although serum potassium and creatinine monitoring before MRA initiation for HF is frequent, rates of post-initiation monitoring remain suboptimal, especially among primary care centres.

Biochemical monitoring after initiation of aldosterone antagonist therapy in users of renin-angiotensin system blockers: a UK primary care cohort study

OBJECTIVE

To determine the frequency of biochemical monitoring after initiation of aldosterone antagonists(AA) in patients also using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEI/ARB).

SETTING

UK primary care.

PARTICIPANTS

ACEI/ARB users who initiated AA between 2004 and 2014.

OUTCOMES

We calculated the proportions with: (1) biochemical monitoring ≤2 weeks post initiation of AA, (2) adverse biochemical values ≤2 months (potassium ≥6 mmol/L, creatinine ≥220 µmol/L and ≥30% increase in creatinine from baseline) and (3) discontinuers of AA in those with an adverse biochemical value. We used logistic regression to study patient characteristics associated with monitoring and adverse biochemical values.

RESULTS

In 10 546 initiators of AA, 3291 (31.2%) had a record of biochemical monitoring ≤2 weeks post initiation. A total of 2.0% and 2.7% of those with follow-up monitoring within 2 months of initiation experienced potassium ≥6 mmol/L and creatinine ≥220 µmol/L, respectively, whereas 13.5% had a ≥30% increase in creatinine. Baseline potassium (OR 3.59, 95% CI 2.43 to 5.32 for 5.0-5.5 mmol/L compared with <5.0 mmol/L) and estimated glomerular filtration rate 45-59 ml/min/1.73 m² (OR 2.06, 95% CI 1.26 to 3.35 compared with ≥60 ml/min/1.73 m²) were independently predictive of potassium ≥6 mmol/L. Women and people with diabetes had higher odds of ≥30% increase in creatinine.

CONCLUSION

Less than one-third of patients taking ACEI/ARB had biochemical monitoring within 2 weeks of initiating AAs. Higher levels of monitoring may reduce adverse biochemical events.

A retrospective analysis of postoperative hypokalemia in pituitary adenomas after transsphenoidal surgery

BACKGROUND

Pituitary adenoma is one of the most common intracranial neoplasms, and its primary treatment is endoscopic endonasal transsphenoidal tumorectomy. Postoperative hypokalemia in these patients is a common complication, and is associated with morbidity and mortality. This study aimed to analyze the etiopathology of postoperative hypokalemia in pituitary adenomas after endoscopic transsphenoidal surgery.

METHODS AND MATERIALS

This retrospective study included 181 pituitary adenomas confirmed by histopathology. Unconditional logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Repeated measures ANOVA was used to analyze change in serum potassium levels at different time points.

RESULTS

Multiple Logistic regression analysis revealed that only ACTH-pituitary adenoma (OR = 4.92, 95% CI [1.18-20.48], P = 0.029) had a significant association with postoperative hypokalemia. Moreover, the overall mean serum potassium concentration was significantly lower in the ACTH versus the non-ACTH group (3.34 mmol/L vs. 3.79 mmol/L, P = 0.001). Postoperative hypokalemia was predominantly found in patients with ACTH-pituitary adenoma (P = 0.033).

CONCLUSIONS

ACTH-pituitary adenomas may be an independent factor related postoperative hypokalemia in patients despite conventional potassium supplementation in the immediate postoperative period.