Differential access to pain medications: comparing metropolitan, micropolitan, small town, and rural pharmacies in Michigan

Rural areas rank poorly on a number of health indicators. Adequacy of pain medication supply at local pharmacies has been an indicator of racial and ethnic disparities in health care. However, the role of these factors in rural disparities is unknown. A cross-sectional survey study combined 2010 census data and data from Michigan community retail pharmacists to explore potential disparities in pain medication availability. Pain medication availability was assessed for change since 2005; sufficient availability was defined as stocking at least one long-acting, short-acting, and combination opioid analgesic. Sufficient pain medication was then defined as stocking at least one medication in any of 14 classes related to treating chronic pain conditions: opioid analgesics, opioid analgesic combinations, opioid agonist-antagonist analgesics, oxycodone hydrochloride, agents for migraine, benzodiazepines, anticonvulsants, sulfonamides, nonsteroidal anti-inflammatory agents, selective cox-2 inhibitors, bupropion, selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors, and tricyclic antidepressants. For the 140 pharmacies contained in zip codes with >70% white residents; availability increased from 86.9% to 96.24% (p<.05). Pharmacies located in rural, small town, micropolitan, and urban zip codes as defined by the census tract-based classification scheme, Rural-Urban Commuting Areas, were randomly selected (response rate, 82.2%). Of the 144 pharmacies surveyed, rural pharmacies were more likely than small town (odds ratio, 3.97) and micropolitan pharmacies (odds ratio, 4.47) to have insufficient pain medication supply (p≤ .005). Because of the high correlation between sufficient supplies in every class and sufficient opioid agonist-antagonist analgesics (r=.856, n=144, p<.001) a second regression was run. After accounting for median household income, pharmacies in rural zip codes were more likely than small town (odds ratio, 4.33) and micropolitan pharmacies (odds ratio, 4.47) to have insufficient opioid agonist-antagonist analgesics (p < .01). This study demonstrates disparities and barriers to rural pain care while having significant public health and policy implications.