Predictive Factors for Incomplete Adherence to Glaucoma Management amongst Singaporean Chinese

Abstract

 

Purpose

 

To investigate the rate and factors (objective and subjective) associated with adherence to treatment in glaucoma patients.

 

Methods

 

Singaporean Chinese patients with primary open angle or angle closure glaucoma currently on topical anti-glaucoma medication were recruited from specialist glaucoma clinics. Socio-demographic data and information about patients’ general and ocular health were collected. Objective adherence was assessed via clinic attendance records (from 1 January 2006 through 30 November 2012) and subjective adherence using the interviewer-administered Modified 8-item Medication Adherence Scale (MMAS). Beliefs towards medicines, glaucoma and eye drops were assessed using validated questionnaires. Patients with full attendance on clinic visits and the maximum possible score of 8 on the MMAS were deemed completely adherent.

 

Results

 

A total of 594 patients were enrolled. Mean (SD) age was 65.3 (10.3) years and 362 (60.9%) were male. 465 (78.3%) patients were diagnosed with primary open angle glaucoma, with a mean deviation (SD) of -13.49 (9.51) on the Humpfrey visual field test. Average duration (SD) since diagnosis was 4.32 (4.47) years. The mean (SD) objective adherence rate was 93.48% (7.76%) over an average (SD) follow-up duration of 4.80 (1.85) years. 223 (37.5%) patients had full attendance for scheduled clinic visits. The mean (SD) subjective adherence using the MMAS was 6.12 (1.72). 281 (47.3%) patients had a MMAS maximum possible score of 8. Overall, 165 (27.8%) patients fulfilled the criteria for complete adherence. Objective and subjective non-adherence were found to be strongly associated (OR [odds ratio] 6.25, 95% CI [confidence intervals] 4.32-9.06, p<0.001). Predictive factors for incomplete adherence included older age (p=0.005), a diagnosis of primary angle closure glaucoma (p=0.002) and a longer duration of disease since diagnosis, [≥4 years] (p=0.023). Beliefs towards medicines, glaucoma and eye drops, and other socio-demographic, ocular and general health factors were not independently associated with non-adherence.

 

Conclusions

 

Elderly patients living with primary angle closure glaucoma for at least 4 years are more likely to default on clinic visits. Targeting this group with disease specific education and reminder strategies for clinic visits and eye drop administration may help to improve glaucoma management.

 

Keywords: 460 clinical (human) or epidemiologic studies: health care delivery/economics/manpower