BMJ Open (Sep 2020)

Prevalence and factors associated with false hyperkalaemia in Asians in primary care: a cross-sectional study (the Unlysed Hyperkalaemia- the Unseen Burden (UHUB) study)

  • Alicia Ying Ying Boo,
  • Pei Lin Hu

DOI
https://doi.org/10.1136/bmjopen-2019-033755
Journal volume & issue
Vol. 10, no. 9

Abstract

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Objective We aimed to determine the prevalence of unlysed false hyperkalaemia and the factors associated with false-and-true-hyperkalaemia.Setting Outpatients in a cluster of public primary care clinics (polyclinics) in Singapore.Participants All patients of any ethnicity aged ≥21 with serum potassium test done.Methods Electronic health records of index patients with potassium >5.5 mmol/L and its corresponding laboratory processing time in seven local polyclinics were reviewed between August 2015 and August 2017. Haemolysed specimens and patients on sodium polystyrene sulfonate (SPS) suspension were excluded. If repeat potassium level was ≤5.5 mmol/L within 8 days, the case was defined as false hyperkalaemia. The proportion of such patients was computed to determine its prevalence. Linear and logistic regressions were used to identify the associated factors.Results The study population comprised of 3014 index cases, of which 1575 had repeat potassium tests without preceding SPS. 86.4% (1362/1575) of them had potassium ≤5.5 mmol/L. The average processing time among specimens with potassium ≥6.0 mmol/L was 50 min longer, compared with those with potassium <5.1 mmol/L. Risk factors significantly associated with false hyperkalaemia included estimated glomerular filtration rate (eGFR) (60–89 mL/min/1.73 m2, OR=3.25, p<0.001;>90 mL/min/1.73 m2, OR=3.77, p<0.001) and delayed laboratory processing time (beta coefficient 0.001, p<0.001).Conclusion The prevalence of false hyperkalaemia was 86.4%. Recommendation to repeat potassium tests may target those with eGFR<60ml/min/1.73m2.