Keywords: type 2 diabetes mellitus, polypharmacy, elderly person, HbA1c,

Background:

A complex and bidirectional relationship exists between polypharmacy and glycaemic control. This study aims to evaluate the relationship between polypharmacy and HbA1c levels in individuals aged 65 years and older diagnosed with type 2 diabetes mellitus (T2DM).

Research questions:

Is there a relationship between polypharmacy and HbA1c levels in patients over 65 years of age with type 2 diabetes mellitus?

Method:

This retrospective study examined the relationship between HbA1c levels and polypharmacy status in patients aged 65 years and older with T2DM who were examined at the Family Medicine outpatient clinic of Düzce University Hospital in 2024. The data obtained were analysed using the SPSS 23.0 software package, and statistical significance was set at p<0.05.

Results:

Of the 1,206 patients, 216 who met the inclusion criteria were included in the study. 55.56% (n=120) of the patients were female, and 44.44% (n=96) were male. The median age of the patients was 71 (min=65, max=89), number of medications they were taking was 7 (min=1, max=22), and HbA1c value was 6.80 mmol/mol (min=4.3, max=13.8). All patients except one had at least one additional chronic disease besides T2DM. It was determined that 73.62% (n=159) of patients used only oral antidiabetics, 1.38% (n=3) used only insulin, and 25% (n=54) used both. In the correlation analysis, a statistically significant positive relationship was found between the number of medications used and HbA1c levels (r=0.256; p<0.001).

Conclusions:

Our study revealed a link between an increase in the number of medications used and an increase in HbA1c levels. This finding suggests that multiple medication use may have adverse effects on glycaemic control and that polypharmacy should be managed with caution. It is important for primary care physicians to regularly monitor medication burden in elderly diabetic patients for metabolic control and patient safety.

Points for discussion:

There may be other reasons besides polypharmacy that affect HbA1c levels.

Will reducing the number of medications taken by patients actually lower their HbA1c levels?

In the few studies that have examined this relationship, no significant association has been found between polypharmacy and HbA1c levels. How can this contradiction in the literature be explained?