Jon Birger Haug

Increased antibiotic use in Norwegian hospitals despite a low antibiotic resistance rate

OBJECTIVES Although antibiotic use and resistance are low in Norway, the situation risks changing for the worse. We investigated trends in antibiotic use and assessed them in relation to antibiotic resistance in Norway. METHODS We drew on hospital pharmacy sales data to record antibiotic use from 2002 to 2007 in eight hospitals serving 36% of the nations population. Antibiotic use was measured using different indices with defined daily doses (DDDs) as the numerator (WHO ATC/DDD classification). RESULTS Total antibiotic use increased from 1.02 to 1.30 DDDs/1000 inhabitants/day (DIDs) and from 61.7 to 72.4 DDDs/100 bed-days (BDs) (17.4%); related to the number of discharges, no significant DDD change was shown. Their use in core units (adult intensive care units, recovery/post-operative wards and departments of internal medicine and surgery with all subspecialties) increased from 64.1 to 80.8 DDDs/100 BDs (26.1%) and by 3.1% related to the number of discharges. The total use of broad-spectrum antibiotics increased by 47.9% when measured as DDDs/100 BDs, and by 19.1% based on the number of discharges; the corresponding figures for core units were 60.5% and 31.2%, respectively. CONCLUSIONS There was a substantial increase in total antibiotic use, and an even more pronounced increase in the use of broad-spectrum antibiotics, which seems unjustified considering the current low antibiotic resistance in Norway.

WHO defined daily doses versus hospital-adjusted defined daily doses: impact on results of antibiotic use surveillance

OBJECTIVES To investigate effects on surveillance results of hospital antibiotic use when WHO defined daily doses (WHO DDDs) are adjusted to doses recommended for hospitalized patients [hospital-adjusted defined daily doses (haDDDs)]. METHODS Data for antibiotic use in 2006-11 for all 22 Norwegian Health Enterprises were analysed with both WHO DDDs and haDDDs as numerators. The haDDDs were determined from recommendations given in regional and national guidelines on antibiotic use in hospitals. The two ways of calculating the amount of antibiotic use were compared, with either the number of bed days (BDs) or the number of discharges as the denominator. The drug utilization 90% methodology was applied for ranking the use of the various antibiotics. RESULTS DDD adjustments altered the figures for total antibiotic use from 67.1 WHO DDDs/100 BDs to 49.3 haDDDs/100 BDs (-26.4%). The most marked difference was found for penicillins: 31.1 WHO DDDs/100 BDs versus 13.4 haDDDs/100 BDs (-56.8%). The corresponding figures for broad-spectrum antibiotics were 17.3 and 15.5 (-10.4%), respectively; for these antibiotics, the conversion changes varied significantly between institutions, from -16.7% to -3.3%. Ranking antibiotic use based on haDDDs resulted in higher positions for metronidazole, cefuroxime, cefotaxime and cefalotin/cefalexin compared with the WHO DDD-based ranking, where the penicillins dominated. CONCLUSIONS The low-set WHO DDDs for penicillins caused skewed surveillance results that concealed the real magnitude of broad-spectrum antibiotic use and distorted interhospital comparisons. For surveillance of antibiotic use in hospitals, WHO DDDs should be supplemented with haDDDs.

Pharmacy sales data versus ward stock accounting for the surveillance of broad-spectrum antibiotic use in hospitals

BackgroundAntibiotic consumption in hospitals is commonly measured using the accumulated amount of drugs delivered from the pharmacy to ward held stocks. The reliability of this method, particularly the impact of the length of the registration periods, has not been evaluated and such evaluation was aim of the study.MethodsDuring 26 weeks, we performed a weekly ward stock count of use of broad-spectrum antibiotics - that is second- and third-generation cephalosporins, carbapenems, and quinolones - in five hospital wards and compared the data with corresponding pharmacy sales figures during the same period. Defined daily doses (DDDs) for antibiotics were used as measurement units (WHO ATC/DDD classification). Consumption figures obtained with the two methods for different registration intervals were compared by use of intraclass correlation analysis and Bland-Altman statistics.ResultsBroad-spectrum antibiotics accounted for a quarter to one-fifth of all systemic antibiotics (ATC group J01) used in the hospital and varied between wards, from 12.8 DDDs per 100 bed days in a urological ward to 24.5 DDDs in a pulmonary diseases ward. For the entire study period of 26 weeks, the pharmacy and ward defined daily doses figures for all broad-spectrum antibiotics differed only by 0.2%; however, for single wards deviations varied from -4.3% to 6.9%. The intraclass correlation coefficient, pharmacy versus ward data, increased from 0.78 to 0.94 for parenteral broad-spectrum antibiotics with increasing registration periods (1-4 weeks), whereas the corresponding figures for oral broad-spectrum antibiotics (ciprofloxacin) were from 0.46 to 0.74. For all broad-spectrum antibiotics and for parenteral antibiotics, limits of agreement between the two methods showed, according to Bland-Altman statistics, a deviation of ± 5% or less from average mean DDDs at 3- and 4-weeks registration intervals. Corresponding deviation for oral antibiotics was ± 21% at a 4-weeks interval.ConclusionsThere is a need for caution in interpreting pharmacy sales data aggregated over short registration intervals, especially so for oral formulations. Even a one-month registration period may be too short.

Are measures against MRSA transmission effective

JON BIRGER HAUG E-mail: jobhau57@gmail.com Jon Birger Haug (born 1957), specialist in infectious diseases and infection control officer at Østfold Hospital Trust. He has led the work on national guidelines for antibiotic use in hospitals and has a PhD degree in antibiotic epidemiology and surveillance methodology in Norwegian hospitals. The author has completed the ICMJE form and declares no conflicts of interest.