Adherence may be most important factor for glaucoma treatment

Ophthalmologists need to be aware of what can influence glaucoma treatment adherence.

Issue: September 2016

Age, the sex of a patient and the type of treatment are among the most significant factors that can influence a patient’s adherence to glaucoma therapy.

Ophthalmologists and optometrists who understand how certain factors can affect adherence to glaucoma treatment can take steps to ensure their patients actively follow the therapy regimen prescribed to them, Norbert Pfeiffer, MD, said at the European Glaucoma Society congress.

“Adherence may be the most important factor for success of glaucoma therapy. It is fair to assume that probably half of visual function is lost to bad adherence among patients,” Pfeiffer said.

Measuring adherence rates

By measuring refills, observing side effects and recording self-reported adherence, Pfeiffer and colleagues were able to measure glaucoma treatment adherence in a German cohort of 201 patients.

Norbert Pfeiffer

Adherence was defined as a patient’s ability and willingness to adhere to a mutually agreed therapy. Pfeiffer and colleagues reported 30.3% of the patients in the cohort did not adhere to the treatment prescribed by their physician.

Men typically adhered less than women, with 63.2% of male patients adhering to their treatment compared with 75.5% of female patients. Age also affected adherence, as the very old and very young adhered less than the middle-aged, he said.

“What about the severity of glaucoma? If you have to see the doctor more frequently, if you are reminded of the disease more frequently, than you have better adherence. In severe disease, adherence is better than if you have just a mild form of the disease. If you have severe disease, then probably you are being given more medication, reminded more often, and this has a positive effect,” Pfeiffer said.

More medications, less adherence

Patients who take one medication a day are moderately adherent. If patients have to take medication more than once a day, then adherence drops. It drops even further if patients have to take more than two medications for glaucoma, Pfeiffer said.

Additionally, patients who knew their diagnosis and the definition of glaucoma had higher adherence than those who did not. Patients who knew their diagnosis had a 70.2% adherence rate compared with 29.8% adherence in patients who did not know their diagnosis. Patients who fully understood their glaucoma diagnosis had a 63.1% adherence rate compared with a 36.9% adherence rate for patients who did not understand their diagnosis, Pfeiffer said.

Pfeiffer noted that the use of medications containing preservatives led to a lower adherence rate.

“If [patients] use medications with preservatives, they are less adherent than if they do not take any preservatives. It is a 20% difference. If they take mixed medications, it is in the middle. Preservatives do tend to irritate the eye,” he said.

Technique

Eye drop instillation techniques can also affect adherence. Many older patients think they are taking their medication correctly and placing drops accurately, but they may not be successfully getting the drops into their eyes.

This is one of the few factors ophthalmologists can actually affect to improve adherence rates, Pfeiffer said.

“Two factors you can change: Adherence goes down with multiple therapies, so try to avoid multiple therapies, or when they are necessary, use mixed combinations. And, finally, again, whatever we prescribe and however few of the side effects there may be, check for technical ability. This will do a great favor to our patients,” he said. – by Robert Linnehan

Reference:
Pfeiffer N. Adherence in glaucoma therapy. Presented at: European Glaucoma Society congress; June 19-22, 2016; Prague.

For more information:
Norbert Pfeiffer, MD, can be reached at Johannes Gutenberg University of Mainz, Langenbeckstraße 1, 55131 Mainz, Germany; email: ellen.pieplau@unimedizin-mainz.de.

Disclosure: Pfeiffer reports no relevant financial disclosures.