Opioid dependence among people with haemophilia in a low-resource tropical setting: prevalence and risk factors in northern Nigeria

Abstract Background In tropical countries such as Nigeria, where factor VIII (FVIII) is scarce, severe pain due to musculoskeletal bleeding complications, leading to frequent opioid prescription, is not uncommon in poorly managed people with haemophilia (PWH). The relationship between opioid use and dependence is intensively studied in other painful diseases, such as cancer and rheumatoid arthritis, but surprisingly little is known about opioid dependence in haemophilia. We hypothesise that the risk of opioid dependence among PWH in tropical countries like Nigeria is multi-factorial, encompassing demographic (age), clinical (haemophilia severity and chronic arthropathy) and biological (ABO blood groups and haemoglobin (Hb) phenotypes) factors that may directly or indirectly increase incidence of bleeding and/or pain. Aims To determine the prevalence of opioid dependence and relative risks (RR) associated with age, haemophilia severity, chronic arthropathy, ABO blood groups and Hb phenotypes, and to elucidate the pathophysiological roles of each risk factor in the development of opioid dependence among haemophilia-A patients in five hospitals in northern Nigeria. Methodology A retrospective review of the medical records of 88 PWH seen between 1996 and 2012 was used to collate data on age, sex, haemophilia severity, painful chronic haemophilic arthropathy, ABO blood group, haemoglobin phenotypes, presence or absence of opioid dependence, and the types of opioids on which the patients were dependent. The prevalence of opioid dependence among the cohort was expressed as a percentage. The frequency of each putative risk factor for opioid dependence in patients with and without opioid dependence were compared using Fisher’s exact test; RR associated with each risk factor was determined by regression analysis. P<0.05 was taken as significant. Results Of the 88 PWH studied,15 (17%) were shown to be opioid-dependent. Compared with PWH who were not opioid-dependent, this group had higher frequencies of severe haemophilia (86.7% vs. 49.3%: RR= 5.2, p=0.02), survival to adulthood (73.3% vs. 12.3%: RR= 9.5, p=0.0001), chronic arthropathy in one or more joints (86.7% vs. 21.9%: RR= 13.2, p=0.0004), blood group-O (80% vs. 49.3%: RR= 3.3, p=0.04), and HbAA phenotype (86.7% vs. 54.8%: RR= 4.3, p=0.04). Conclusion Prevalence of opioid dependence among PWH treated at five hospitals in northern Nigeria was 17% during the study period. Significant risk factors were directly or indirectly associated with increased rates of bleeding and/or pain, which can only be prevented or treated through optimal application of FVIII. There is a need for the Nigerian government to establish standard haemophilia care centres with adequate FVIII for optimal prophylaxis and treatment in order to minimise painful complications, thereby helping to prevent undue opioid use and dependence.