From toy to tool: Using water beads for insulin storage in Haiti

Diabetes prevalence within the global population has nearly doubled since 1980, with the most rapid growth occurring in low- and middle-income countries. Diabetes management in resource-limited settings such as Haiti presents many challenges, including the storage of insulin. Despite a lack of published data on insulin thermostability, storage at 2-8°C or at room temperature (25°C) is recommended. In Haiti, access to refrigeration and thereby proper insulin storage is severely limited. Commercial storage devices such as the FRIO cooling wallet are cost-prohibitive and not available locally, and alternatives such as small clay pots are fragile and nonportable. Here, we designed and tested the cooling efficacy of a homemade wallet made of acrylate polymer beads and a hand-sewn cotton pouch compared to a FRIO wallet and a clay pot. All studies were conducted over a ten-day period at the Kay Mackenson Clinic in Montrouis, Haiti. Temperature and humidity values were continuously collected using wireless monitors placed inside each device, and hourly ambient temperature and humidity values were manually recorded. Evaporative cooling efficacy was calculated using collected data. The homemade wallet and FRIO cooling wallet demonstrated comparable cooling efficacy with an average of 71% and 73%, respectively. The clay pot demonstrated significantly decreased efficacy with an average of 27% (p < 0.05). The homemade insulin wallet is a promising alternative for the storage of insulin in low-resource settings without the financial and physical barriers of commercial and locally sourced devices. Additionally, this wallet could be readily adapted for the storage of other perishable medical supplies in low-income countries.