Antibiotic use and resistance patterns in the Namibian private health sector

Abstract

The general aim of this study was to understand antibiotic use in the private health sector of Namibia. Specifically, the study set out to ascertain the relationship, if any, between prescribing patterns, antibiotic use and antibiotic susceptibility patterns. The study employed a mixed method approach, using a mixture of surveys and available data from databases to examine the association between antibiotic use and local resistance, prescribing practices, consumer behaviour as well as knowledge of antibiotics. A retrospective analysis of antibiotic wholesale data and prescription claims data from a medical insurance fund administrator for the period 2008 to 2011 were used to quantify trends in antibiotic use. Laboratory annual antibiogram reports for 2005 to 2011 were used for sensitivity data. Cross-sectional surveys based on self-administered questionnaires were used to determine prescriber practices and patient knowledge and behaviour regarding antibiotics use. Six hundred questionnaires were distributed to patients through community pharmacies in Windhoek and the data were collected between 1 March 2013 and 30 June 2013. The doctors' survey employed a web-based questionnaire which was distributed through professional associations. This data were collected from 1 March 2014 to 31 July 2014. The study uncovered high antibiotic usage (26.8 DDD/1000/day) in the private sector of Namibia with increasing trends in usage over the study period. An overall 25% increase in antibiotic usage was observed over the four-year period. Antibiotic usage was the highest among females (53%) and in the age group 18 to 45 years (41%). It was also the highest in Windhoek, the capital (34%). Overall, wholesale data showed higher antibiotic use than prescription claims data obtained from the medical insurance fund administrator. However, both sources showed similar patterns of antibiotic use. Penicillins were the highest used pharmacological group, followed by cephalosporins and macrolides. The most commonly used active ingredients were amoxicillin with clavulanic acid (8.25 DID prescription claims; 8.32 DID wholesale); cefuroxime (5.94 DID prescription claims; 6.23 DID wholesale) and clarithromycin (3.2 DID) for prescription claims data and doxycycline (4.05 DID) for wholesale data. The study further found a preference for broad spectrum and newer antibiotics. Consumption patterns observed in the private sector of Namibia are not unique and compare with those in various European countries as well as other developed and developing countries. Prescriptions claims data were found to be a more reliable data source for the quantification of antibiotic use because calculations have been validated by the medical insurance fund administrator and are also close to actual consumption data, that is, actual quantities dispensed to the patient. Resistance trends showed very slight changes over the years. The greatest resistance was observed with chloramphenicol (18%). E. coli and S. aureus showed great resistance to amoxicillin (23% and 7%, respectively). Older antibiotics showed greater resistance patterns compared to newer antibiotics. A year-on-year comparison of resistance and use showed no correlation. However, increases in statistical significance were observed when correlating use in earlier years with sensitivity of later years showing that resistance is a function of use and time. Correlating earlier antibiotic use with later resistance also showed that, as the volume of antibiotic consumption increases, the time to reach the same strength of correlation is shorter. This shows that an increase in the volume of antibiotic consumption increases the selection pressure for the development of resistance. As with consumption patterns, resistance patterns observed in this study are not peculiar to the Namibian private sector, but are similar to those reported elsewhere in Africa, including South Africa. The study revealed that both awareness of local antimicrobial sensitivity rates and ownership of national standard treatment guidelines among prescribers were poor (20% and 31%, respectively). The common practice among prescribers was to treat community-acquired infections empirically. The reported first-line antibiotics of choice were the combination of amoxicillin with clavulanic acid for upper respiratory tract infections and ciprofloxacin for urinary tract infections. Antibiotic prescribing was not in line with national standard treatment guidelines and for most common outpatient infections, prescribing were also not in line with local sensitivity patterns. Assessing public knowledge and behaviour confirmed that antibiotic usage is high in the private sector and that antibiotics are used mainly for respiratory tract infections (specifically colds and flu symptoms). The study further revealed a prevalence of 15% of self-medication with antibiotics mainly obtained from pharmacies without a prescription. On a positive note, the study uncovered that only 14% of the public reported that they request antibiotics and 80% reported that they complete their antibiotic course. Gaps in the public's understanding of antibiotics were observed. Sixty-four percent (64%) of the public respondents thought that antibiotics were effective against viruses with just less than half admitting that they should take an antibiotic for a cold. On the other hand, 72% of respondents understood that the unnecessary use of antibiotics makes them ineffective. In order to improve prudent use of antibiotics in Namibia, it is important to regularly monitor antibiotic use and resistance patterns in both the public and private sector. Measures to discourage the over-the-counter sale of antibiotics, promote rational prescribing, encourage adherence to national standard treatment guidelines, increase awareness of local sensitivity patterns and educate patients on antibiotics and their use should be explored and implemented.