I went on a outreach trip to Molepolole with Stephanie, a BIPAI pediatrician and Baylor College of Medicine graduate. My intention joining her was to test out my pill counter and adherence charts. The pill counter is a mechanical diamond scale, accurate to 0.01g, which I use to weigh pills. The theory behind the design is if you know the weight of an individual pill, you know the weigh of the sample given.
Knowing pill counts is an extremely important component to evaluating a patient’s HIV treatment. If you know how many pills are left in a patient’s pill bottle, you know how well they have adhered to a therapy (pills taken/pills prescribed). For an ARV therapy to work effectively, patients must adhere to between 95%-105%. Any lower, the patient runs the risk of their HIV virus developing resistance to the drugs. Any higher, the drug reaches toxic levels.
Pill counting and calculating adherence rates is a time consuming process that is prone to human error. Rather than manual counting pills and doing the math for the adherence rate, I proposed a system whereby a health professional could use the scale to quickly weigh the pills, obtain a count, and then use my charts to determine the rate. I created an adherence chart for each type of regimen (1 per day, 2 per day, three per day) over periods of 30 and 60 days. To read the chart, you simply need the number of days since you last saw the patient and the number of pills left in their bottle. The chart would provide you with the percentage adherence, thereby eliminating any calculation.
Unfortunately, my design did not account for a number of constraints at clinics. First, ARV pills are HUGE. I was wrong to think that pediatric ARVs would be about the same size (or smaller) than the Aleve/Ibuprofen I tested it on. At the BIPAI clinic, patients often see a physician in the middle of a 3 month regimen. Because the scale container is quite small, it cannot hold the dozens of pills each patient brings back. Second, pharmacies often dispense more pills than necessary because they assume a patient might not be able to make it exactly a month later. Patients would have 4 pills left in their bottles even though they had adhere 100% to the treatment.
Realizing that my designs would not work, I decided to make something up on the spot. I noticed that the nurses had some difficulty doing calendar math (e.g., if a patient last came on 4/23/2010 and today is 5/31/2010, how many days has it been?). I found some blank sheets of paper and created a calendar for May and April. I then counted backwards from today so one could jump to the previous appointment date and know how many days have passed. But the moment I tried this design it also failed. Nurses sometimes had to calculate the days of treatment with the end date being other than today (e.g., patient treated from 4/23/2010 to 5/24/2010, even though today is 5/31/2010).
The major challenge to the Beyond Traditional Borders program and Global Health Minor is creating technologies for clinics and situations that are thousands of miles away from Houston. I had no access to ARVs and had never witnessed a nurse counsel a patient on adherence. Although my designs failed, I will work to adapt them while here. The problem with the scale could easily be resolved with a digital solar powered scale. That way it would require no plug in power and could hold a large amount of pills. I still do not know how to help with adherence measurements. At the moment, I have an excel file where one can input the dates of treatment and it will give you the difference between them. Given all the constraints, weighing pills and calculating adherence without a computer remains a challenge.