Study of the Impact of Anxiety and Depression on Weight Loss Medication Adherence

Purpose: Obesity is associated with depression and anxiety. Medication adherence can impact and impose burden on health outcomes and costs. Studies have shown that depressed patients are less likely to take medications. Non-adherence to weight loss (WL) medication may negatively impact on outcomes, such as improvement of cardiovascular risk and quality of life. However, there are no published studies evaluating the influence of depression and anxiety and WL medication adherence.   

Methods: These are interim 3-month results from a 12-month double-blind, randomized, parallel-group controlled trial. Fifteen obese (BMI ≥30) subjects, 40-75 y.o., randomized to three active medications/placebos (BID or TID) in five different combination WL pharmacotherapy groups. Depression evaluated using Beck Depression Inventory II (BDI-II) and anxiety evaluated using the Beck Anxiety Inventory (BAI). Medication adherence was calculated using cumulative 3-month pill count, using the equation:  (Amount dispensed – Pill count)/Amount expected

Results: The interim analyses shows WL data for n=15 (8 female): age 53±7 yrs; BMI 36±4; BAI score 6.0±6.7; BDI-II score 6.9±7.7. At the 3-month follow-up, BMI, BAI and BDI-II scores decreased significantly to: BMI 32±4 (p<0.0001); BAI 4.0±6.0 (p=0.032); and BDI-II 3.5±4.6 (p=0.006), respectively. Mean study medication adherence for all three medications was 97% ± 2. Mean adherence for the combined three medications was not associated with either depression (p=0.5536) or anxiety scores (p=0.4972). Interestingly, the TID agent adherence and changes in BAI scores show a correlation estimate of -0.49339 (p= 0.0632).  

Conclusion:  At the 3-month period adherence with WL medications is very high. This may have adversely impacted our ability to detect an effect of anxiety or depression on adherence. Additionally, even within this short follow-up substantial reductions were seen in anxiety and depression. Future analyses will include more subjects followed over a longer period of time.