Characteristics and the determinants of high volume dispensing in long-term oral nutritional supplement users in primary care

Background Oral nutritional supplements (ONS) are recommended for patients at risk of malnutrition or malnourished. Appropriate ONS prescribing requires regular monitoring to assess its continued requirement. Previous research identified long-term ONS prescriptions (>6 months) without review, with 70% of these influenced by social factors.

Aim To investigate the characteristics of ONS long-term users in Ireland and the determinants of larger volumes of ONS dispensing.

Design and setting Secondary analysis of anonymous dispensed pharmacy claims data of patients dispensed standard ONS for 12 consecutive months in 2018 (n=912).

Method Factors showing significant (P<0.05) univariate associations with above the median consumption of ONS units were entered into a multivariable model.

Results Median age was 76 (range 18–101) years, with 66.9% of the sample being ≥65 years. Almost 70% of our sample was on polypharmacy (45.6%;≥5 medications) or excessive polypharmacy (21.5%;≥10 medications). Younger age and being on polypharmacy for drugs having an effect on the central nervous system (CNS) were significantly associated with being dispensed more ONS units in univariate and multivariate analysis. Those patients in the age range 18–44 were 2.5 fold more likely to be prescribed more ONS units (OR 2.5; 95% CI 1.5–4.25;P<0.001). Patients using CNS drugs or on CNS polypharmacy were more likely to be prescribed more ONS units (ORs 1.24 and 2.35; 95% CI 0.86–1.41 and 1.25–4.41 respectively; P=0.029).

Conclusion Older age and polypharmacy characterise long-term ONS users in this study. Younger age and CNS medication polypharmacy are predictors of more ONS units prescribed over a year.