RISK FACTORS FOR HYPOTHYROIDISM IN PATIENTS ON PERITONEAL DIALYSIS (PD)

Hypothyroidism is a common occurrence in patients on PD and our centre began screening with thyroid function test for all new PD patients since 2012, which was eventually incorporated into the PD training protocol. While loss of thyroxine-binding globulin (TBG) with PD and iodide excess from reduced renal excretion had been proposed, it is unclear who are at risk of the condition.

To determine risk factors associated with hypothyroidism in PD patients.

This was a prospective cohort study, which included all new PD patients without prior thyroid disease between January 2012 to March 2018.  Patients were followed up for the development of hypothyroidism up to March 2018. Demographic, clinical and biochemical data were collected and compared between patients with and without hypothyroidism. Uni- and multivariate logistic regression were performed, with a model of best fit obtained through backward modelling. 

Of 150 patients included in the study population (Age 64.5±13.6, 50% Male, 74.2% diabetic, 59.3% cycler-based PD), 42 (28%) were diagnosed with hypothyroidism, with a median time to diagnosis of 45.6 months (Inter-quartile range: 8.1-230.1). On univariate analysis, only higher drain volume was associated with hypothyroidism (OR 1.44, 95%CI 1.08-1.91). A model of best fit was obtained with variables listed in the table, which demonstrated that hypothyroidism was associated with higher BMI, slower PET status and higher Kt/V.

Whilst a high BMI may be reflective of the hypothyroid state, a higher PD dose, with greater Kt/V and drain volumes, could cause more TBG removal. The relationship between hypothyroidism and a slower PET status requires further investigation.