SCOTTSDALE, ARIZ. (FRONTLINE MEDICAL NEWS) – Although cost-effective, a mobile phone appointment reminder service only minimally increased attendance rates at dermatology outpatient clinics, according to a large longitudinal study.

“There was a small, statistically significant increase in attendance at the adult dermatology clinic, but there was very little effect at satellite and specialty dermatology clinics,” said Dr. Noori Kim of Johns Hopkins University in Baltimore.

Baseline attendance rates were high, exceeding 80%, so perhaps mobile phone appointment reminders have little effect in that setting, she said. In addition, most reminders were by phone call, not text, which could have limited their efficacy if patients did not answer the phone or listen to their voicemail, Dr. Kim added during an oral presentation at the annual meeting of the Society for Investigative Dermatology.

When patients miss medical appointments, it’s usually because they forget them. In this study, the first to assess mobile phone appointment reminders in dermatology, the investigators compared daily attendance at Johns Hopkins outpatient dermatology clinics before and after implementing an automated mobile phone appointment reminder system. The baseline time period without the service spanned four months in 2014, while the comparison period with the system covered the same four-month period a year later.

Patients kept 90% of 11,455 dermatology appointments scheduled during the pre-service period. A year later, the attendance rate was nearly identical, at 89%. Likewise, there were no statistically significant changes in attendance at Johns Hopkins specialty, satellite, pediatric dermatology, and pediatric laser clinics.

In contrast, attendance at the adult dermatology clinic rose by about three percentage points after the service was implemented, from 81% (2,530 visits attended of 3,141 scheduled) to 84% (2,965 visits attended of 3,533 scheduled), and the difference was statistically significant.

“About 88% of reminders were answered across sites, with little variance. The cost was about $5,500 for a 17-month period,” Dr. Kim said. She noted that 71% of patients opted into the service at the adult clinic with the increased attendance rate, compared with about 30% of patients at the other clinics that showed no statistically significant increase in attendance rates.

The “strong continuity already present between patients and providers” and high baseline attendance rates might have limited any effects of mobile phone messaging at these other clinics, she said. Attendance rates also did not change significantly at three Johns Hopkins dermatology clinics that never implemented mobile phone reminders, she noted.

Dr. Kim reported no funding sources and had no disclosures.