In new research findings published in BMJ Open Ophthalmology investigators from Denmark conducted an observational registry study to analyze patterns in glaucoma medication adherence among Danish patients.
Give me some background first.
The use of topical eye drops for glaucoma has been associated with adherence challenges due to the self-effort required and the asymptomatic nature of glaucoma.
Poor medication adherence in glaucoma patients has been attributed to:
- Difficulty administering eye drops
- Physical inability to self-administer eye drops
- Cost of medication
- Side effects
- Difficulty remembering to take medication at the right dose and time
Now, talk about the study.
The register-based study included 30,100 Danish participants who were followed for 10 years between 2000 and 2018 from their first redeemed prescription of glaucoma medication or the first registration of a POAG diagnosis (whichever came first).
The researchers utilized logistic regression models to estimate patient characteristics related to medical adherence.
Let’s go into specifics on these participants.
Participants included individuals aged 18+ who were diagnosed with glaucoma and identified as having either:
- A minimum of three redeemed prescriptions of glaucoma medication in the Register of Pharmaceutical Sales
- Registered with a diagnosis of primary open-angle glaucoma (POAG) in the Danish National Patient Register (DNPR) with a minimum of one redeemed prescription of glaucoma medication
Findings?
Better adherence to eyedrop treatment for up to 10 years was associated with:
- Increasing age
- 70% were aged 60+
- Female sex (60.6%)
- Low comorbidity score
And the data?
The investigators reported:
- 54.7% of participants adhered to their glaucoma treatment
- 51.8% of participants were adherent in the first 2 years
High adherence in the first year(s) of treatment was less likely among:
- Men
- Odds ratio (OR); 0.78
- Younger individuals and among those with a positive Charlson Comorbidity Index (CCI) score
- ≥3 (OR: 0.71)
Adherence in the first year and first 2 years was associated with:
- More adherence in the fifth year
- OR: 4.55 in the first year
- OR: 6.47 in the first 2 years
- More adherence in the tenth year with slightly lower estimates
- OR: 2.81 in the first year
- OR: 3.36 in the first 2 years
Go on …
The researchers found that in terms of cost:
- Being medically adherent was associated with higher costs related to glaucoma medication after 5 to 10 years compared to poor adherence
- Poor adherence was associated with a marked increase in long-term costs for hospital contacts
Limitations?
The authors noted the risk of miscalculation, as adherence was calculated based on data from redeemed prescriptions and assumed each participant was recommended to take one defined daily dose (DDD) of redeemed medication per day.
They added that they could not confirm whether patients were using the redeemed medication or if they administered treatment correctly.
What else?
Additionally, they noted that socioeconomic status may work as a confounder for some of the analyses performed and may have been overestimated, since there was no access to the socioeconomic status of participants in the data.
Lastly, the study excluded participants who were not alive in a period of 10 years from the time of glaucoma diagnosis, which excluded the oldest participants in the population (primarily men) and individuals with a high CCI score.
This overrepresented women and younger individuals in the sample.
Expert opinion?
The authors stated their conclusions could be valuable to physicians and may, “lead physicians to investigate other IOP-lowering options sooner in patients with poor adherence, particularly among those that are progressing at unsafe rates.”
Take home.
These findings emphasize the importance of high adherence to glaucoma treatment in the first few years and could serve as a predictor for future adherence.