Antibiotic recommendations of Canadian physicians: 2007-2011

Volume 40 S-2, November 7, 2014: Antimicrobial resistance

Surveillance

Antibiotic recommendations of office-based physicians, 2007−2011

Finley R1*

Affiliation

1 Centre for Food-borne, Environmental and Zoonotic Infectious Diseases, Public Health Agency of Canada, Guelph, ON

Correspondence

rita.finley@phac-aspc.gc.ca

DOI

https://doi.org/10.14745/ccdr.v40is2a03

Abstract

Objective: To describe patterns of antibiotic recommendations by office-based physicians from five regions in Canada between 2007 and 2011.

Methods: Values were estimated based on quarterly data from a sample of approximately 652 physicians stratified by region and specialty. For four consecutive quarters, each physician maintained a practice diary describing information on every patient visit during a randomly selected 48-hour period. This information was then extrapolated using a projection factor to estimate prescriptions by all physicians across Canada.

Results: Over the five-year surveillance period, physicians saw patients for almost 1.5 billion diagnoses with approximately 120 million antimicrobial recommendations. In 2011 alone, 289 million clinical diagnoses were made of which 8% resulted in an antimicrobial being recommended. The majority of these (51%) were for the treatment of diseases of the respiratory system, 14% for infections of the urinary tract, and 11% for diseases of skin and subcutaneous tissue. Antimicrobial recommendations were highest for patients in the age groups of 0-2, 3-9, and 65 or older. Antimicrobial recommendation rates generally decreased between 2007 and 2011 except for diseases of the genitourinary system and diseases of the ear that remained stable. Overall, the most commonly recommended antimicrobials included macrolides, penicillins with extended spectrum, and fluoroquinolones. Although not as common, there was a 42% increase in the number of physician recommendations for third generation cephalosporins.

Conclusion: With the exception of third generation cephalosporins, the percentage of antimicrobial recommendations by office-based physicians in Canada remained stable or decreased between 2007 and 2011. Provincial differences were observed in the antimicrobial recommendations and rates, with the Atlantic region and Québec having higher rates of antimicrobial recommendations compared to the overall national level.

Introduction

The Canadian Integrated Program for Antimicrobial Resistance Surveillance (CIPARS) monitors trends in antimicrobial use and antimicrobial resistance in selected bacterial organisms from human, animal and food sources across Canada. The Program is based on several representative and methodologically unified surveillance components that can be linked to examine the relationship between antimicrobials used in food animals and humans, and the associated health impacts. This information supports: (i) the creation of evidence-based policies to control antimicrobial use in hospital, community, and agricultural settings, and thus prolong the effectiveness of these drugs; and (ii) the identification of appropriate measures to contain the emergence and spread of resistant bacteria between animals, food, and people in Canada.

The human antimicrobial use surveillance reports are published on a regular basis to provide a national overview of current antimicrobial use practices in Canada annually, to enable comparisons and to support formulary and stewardship development. The objective of this paper is to summarize the most recent CIPARS report that describes patterns of antibiotic recommendations by office-based physicians from five regions in Canada between 2007 and 2011 Footnote 1.

Methods

The Canadian Disease and Therapeutic Index (CDTI) dataset is purchased by the Public Health Agency of Canada from IMS Health Canada Inc. This dataset provides information about the patterns and treatments of disease encountered by office-based physicians from five regions: Atlantic (New Brunswick, Newfoundland and Labrador, Nova Scotia, and Prince Edward Island), Québec, Ontario, the Prairies (Alberta, Manitoba, and Saskatchewan), and British Columbia. Values are estimated based on quarterly data from a sample of approximately 652 physicians stratified by region and specialty. For four consecutive quarters, each physician maintains a practice diary describing information on every patient visit during a randomly selected 48-hour period. This information is then extrapolated using a projection factor to estimate the "universe" comprised of approximately 52,959 physicians, roughly representing all Canadian data.

The information contained in this analysis is for antimicrobials for which a physician has provided a recommendation or prescription, and does not represent actual prescriptions dispensed by pharmacists or consumed by the patient. This data does not include patient visits to a primary care nurse, and diagnosis visits do not translate into the total number of patients, as some patients visited multiple times for the same reason or were diagnosed with multiple diseases. Due to the methods of data collection, sample size is sometimes considered too small for decision making. However, information is still included in this analysis to provide a view of practices which may require further study.

Results

Over the five-year surveillance period (2007-2011) physicians saw patients for almost 1.5 billion diagnoses and provided a total of approximately 121 million antimicrobial recommendations Footnote 1. In 2011, a total of 289 million clinical diagnoses were made of which 8% resulted in an antimicrobial recommendation (Table 1). During that year, out of all the antimicrobials recommended by office-based physicians, 51.3% were for treatment of diseases of the respiratory system followed by infections of the urinary tract (14.5%) and diseases of the skin and subcutaneous tissue (11.3%).

Table 1. Total number of office-based diagnoses, diagnosis rate, total number of antimicrobial recommendations, antimicrobial recommendation rate, and percentage of diagnoses with antimicrobial recommendations by office-based physicians in Canada, by diagnostic class, 2011
Diagnostic class Total diagnoses Total diagnoses / 10,000 inhabitants Antimicrobial recommendations (N) Total antimicrobial recommendations / 10,000 inhabitants Percentage diagnoses with antimicrobial recommendations
Complications of pregnancy, childbirth, and puerperal 1,044,850 302 17,180 5 1.6
Congenital anomalies 925,330 267 21,290 6 2.3
Diseases of blood/blood-forming organs 2,593,490 749 45,160 13 1.7
Diseases of skin and subcutaneous tissue 21,784,200 6,295 2,551,830 737 11.7
Diseases of the central nervous system 10,591,580 3,061 148,900 43 1.4
Diseases of the circulatory system 33,884,750 9,791 62,510 18 0.2
Diseases of the ear 7,627,370 2,204 2,232,080 645 29.3
Diseases of the gastrointestinal system 1,674,160 484 107,900 31 6.4
Diseases of the genitourinary system 12,878,470 3,721 821,180 237 6.4
Diseases of the respiratory system 37,079,860 10,715 11,628,520 3,360 31.4
Endocrine, nutritional, metabolic, and immunity diseases 28,537,420 8,246 62,310 18 0.2
Infections of the urinary tract 6,951,220 2,009 3,285,390 949 47.3
Injuries and poisonings 11,575,360 3,345 317,020 92 2.7
Musculoskeletal diseases 28,086,920 8,116 136,030 39 0.5
Neoplasms 7,124,130 2,059 93,740 27 1.3
Other diseases of the digestive system 17,401,060 5,028 684,730 198 3.9
Perinatal conditions 438,380 127 14,540 4 3.3
Supplementary classifications 37,076,290 10,714 77,420 22 0.2
Symptoms and ill-defined conditions 21,771,660 6,291 359,500 104 1.7
Total 289,046,500 83,524 22,667,230 6,550 7.8

Antimicrobials were recommended to all age groups in 2011, with proportionally higher recommendation rates to patients in the age group 0-2 years (12 antimicrobial recommendations per 10 inhabitants); 3-9 years (9 antimicrobial recommendations per 10 inhabitants); and 60-64 years, and 65 years of age or older (7 antimicrobial recommendations per 10 inhabitants for each age group) (Table 2).

Table 2. Diagnosis rate, antimicrobial recommendation rate and percentage of diagnosis with antimicrobial recommendation provided by office-based physicians in Canada, by age group and by gender, 2011
Demographics: age (year) or gender Number of diagnoses / 10 inhabitants Table 2 - Footnote 1 Antimicrobial recommendations / 10 inhabitants Table 2 - Footnote 2 Percentage of diagnoses with antimicrobial recommendations
Age
1Diagnosis does not represent the number of times a person visits, but represents every time a diagnosis is provided; if a person presents multiple diseases each individual disease/diagnosis is recorded separately.
2Data does not represent actual prescriptions dispensed by pharmacists or products consumed by the patient, as information on patient compliance was not available.
0 to 2 123 12 9.7
3 to 9 52 9 16.5
10 to 19 42 6 13.0
20 to 39 59 6 10.7
40 to 59 81 5 6.6
60 to 64 122 7 5.5
65 or older 152 7 4.9
Gender
Female 93 7 7.7
Male 71 6 8.0

For the most part, the percentage of antimicrobial recommendations by office-based physicians in Canada remained stable or decreased between 2007 and 2011 (Figure 1). Slight increases were seen related to complications of pregnancy, childbirth, and puerperal; congenital anomalies; diseases of the gastrointestinal system; injuries and poisonings; and perinatal conditions.

Figure 1: Percentage of diagnoses that received an antimicrobial recommendation by office-based physicians in Canada, 2007, 2010, and 2011

Figure 1
Text equivalent - Figure 1

Figure 1: Percentage of diagnoses that received an antimicrobial recommendation by office-based physicians in Canada, 2007, 2010 and 2011

This figure is a histogram showing the percentage of diagnoses that received an antimicrobial recommendation by office-based physicians in Canada, in 2007, 2010 and 2011. The y axis represents different diagnostic classes. The x axis represents percentage of antimicrobial recommendations and ranges from 0 at unity to 60% at the far right. The most common condition to result in an antimicrobial recommendation was infections of the urinary tract; slightly more than 50% of the time in 2007 and slightly less than 50% of the time in 2010 and 2011. The second most common condition was diseases of the respiratory tract with antibiotic recommendations more than 30% of the time, with a slight decrease from 2007 to 2011. The third most common condition was disease of ear with antibiotic recommendations slightly less than 30% of the time and a slight decrease from 2007 to 2011. The fourth most common condition was diseases of the skin and subcutaneous tissue with antibiotic recommendations more than 10% of the time with a slight increase in 2010 compared with 2007 and 2011. The fifth and sixth most common conditions were diseases of the gastrointestinal system and genitourinary system with antibiotic recommendations slightly more than 5% of the time. All the other conditions resulted in an antimicrobial recommendation less than 5% of the time; there were virtually no antibiotic recommendations for diseases of the circulatory system and endocrine, nutritional, metabolic and immune diseases.

The most commonly recommended antimicrobials in 2011 were the macrolides (1,638 recommendations per 10,000 inhabitants), penicillins with extended spectrum (1,504 recommendations per 10,000 inhabitants), and the fluoroquinolones (1,202 recommendations per 10,000 inhabitants). However, high increases in the number of physician recommendations were observed for third generation cephalosporins (a 42% increase compared to 2007) due to an increase in recommendations for treatment of diseases of the respiratory system, diseases of the genitourinary system, and infections of the urinary tract.

Provincial variation in the total number of antimicrobial recommendations per 10,000 inhabitants was observed, with the Atlantic region (7,101 recommendations per 10,000 inhabitants) and Québec (8,268 recommendations per 10,000 inhabitants) having the highest rates compared to the overall national level. Rates of diagnoses and antimicrobial recommendations per 10,000 inhabitants varied depending upon the province and disease of treatment. Provincial preferences for antimicrobial of choice for treatment of disease were also observed (Table 3).

Table 3. Diagnosis rate, antimicrobial recommendation rate and percentage of diagnoses with antimicrobial recommendations provided by office-based physicians in Canada, by diagnostic class and by province/region, 2011
Diagnostic class Province / region Number of diagnoses / 10,000 inhabitants Table 3 - Footnote 1 Antimicrobial recommendations / 10,000 inhabitants Table 3 - Footnote 2 Percentage of diagnoses with antimicrobial recommendations
1Diagnosis does not represent the number of times a person visits, but represents every time a diagnosis is provided; if a person presents with multiple diseases each individual disease/diagnosis is recorded separately.
2Data does not represent actual prescriptions dispensed by pharmacists or products consumed by the patient, as information on patient compliance was not available.
3NAS = no antimicrobials suggested (recommended).
4The Prairies include the provinces of Alberta, Saskatchewan, and Manitoba.
5The Atlantic region includes the provinces of New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland and Labrador.
Complications of pregnancy, childbirth, and puerperal British Columbia 350 NAS Table 3 - Footnote 3 NAS
Prairies Table 3 - Footnote 4 303 3 1.1
Ontario 271 NAS NAS
Quebec 330 19 5.7
Atlantic Table 3 - Footnote 5 298 NAS NAS
Total 302 5 1.6
Congenital anomalies British Columbia 374 10 2.7
Prairies 265 13 4.7
Ontario 171 5 2.9
Quebec 296 NAS NAS
Atlantic 530 10 1.9
Total 267 6 2.3
Diseases of blood/blood-forming organs British Columbia 715 NAS NAS
Prairies 665 12 1.8
Ontario 744 20 2.7
Quebec 707 13 1.9
Atlantic 1,242 NAS NAS
Total 749 13 1.7
Diseases of skin and subcutaneous tissue British Columbia 7,602 820 10.8
Prairies 6,061 706 11.6
Ontario 5,866 792 13.5
Quebec 6,399 664 10.4
Atlantic 6,741 631 9.4
Total 6,295 737 11.7
Diseases of the central nervous system British Columbia 3,472 73 2.1
Prairies 2,440 33 1.3
Ontario 3,297 39 1.2
Quebec 3,020 37 1.2
Atlantic 2,811 57 2.0
Total 3,061 43 1.4
Diseases of the circulatory system British Columbia 9,503 48 0.5
Prairies 9,231 5 0.0
Ontario 9,479 19 0.2
Quebec 1,037 8 0.8
Atlantic 12,081 24 0.2
Total 9,792 18 0.2
Diseases of the ear British Columbia 2,285 349 15.3
Prairies Table 3 - Footnote 4 1,628 460 28.2
Ontario 1,708 514 30.1
Quebec 3,123 1,168 37.4
Atlantic Table 3 - Footnote 5 3,348 702 21.0
Total 2,204 645 29.3
Diseases of the gastrointestinal system British Columbia 452 53 11.6
Prairies 521 9 1.7
Ontario 461 29 6.4
Quebec 530 28 5.3
Atlantic 445 69 15.6
Total 484 31 6.4
Diseases of the genitourinary system British Columbia 3,646 207 5.7
Prairies 3,500 252 7.2
Ontario 3,606 218 6.0
Quebec 3,815 277 7.3
Atlantic 4,957 243 4.9
Total 3,722 237 6.4
Diseases of the respiratory system British Columbia 9,699 2,649 27.3
Prairies 10,193 3,307 32.4
Ontario 9,687 3,000 31.0
Quebec 13,044 4,377 33.6
Atlantic 12,504 3,641 29.1
Total 10,715 3,360 31.4
Endocrine, nutritional, metabolic, and immunity diseases British Columbia 7,353 NAS Table 3 - Footnote 3 NAS
Prairies 6,940 14 0.2
Ontario 8,557 23 0.3
Quebec 8,477 28 0.3
Atlantic 11,215 5 < 0.1
Total 8,247 18 0.2
Infections of the urinary tract British Columbia 2,241 982 43.8
Prairies 1,886 825 43.8
Ontario 1,869 855 45.7
Quebec 1,891 1,143 60.5
Atlantic 3,164 1,134 35.8
Total 2,009 949 47.3
Injuries and poisonings British Columbia 5,400 99 1.8
Prairies Table 3 - Footnote 4 3,446 93 2.7
Ontario 2,864 94 3.3
Quebec 3,221 90 2.8
Atlantic Table 3 - Footnote 5 2,398 73 3.0
Total 3,345 92 2.7
Musculoskeletal diseases British Columbia 8,402 4 < 0.1
Prairies 8,748 53 0.6
Ontario 7,911 56 0.7
Quebec 6,804 13 0.2
Atlantic 11,928 69 0.6
Total 8,116 39 0.5
Neoplasms British Columbia 2,012 10 0.5
Prairies 1,630 3 0.2
Ontario 1,840 8 0.5
Quebec 2,645 95 3.6
Atlantic 2,614 NAS Table 3 - Footnote 3 NAS
Total 2,059 27 1.3
Other diseases of the digestive system British Columbia 4,925 237 4.8
Prairies 5,460 138 2.5
Ontario 4,547 214 4.7
Quebec 4,962 224 4.5
Atlantic 7,311 106 1.5
Total 5,028 198 3.9
Perinatal conditions British Columbia 123 NAS NAS
Prairies 154 16 10.1
Ontario 151 NAS NAS
Quebec 96 6 6.5
Atlantic 35 NAS NAS
Total 127 4 3.3
Supplementary classifications British Columbia 10,174 12 0.1
Prairies 12,776 9 0.1
Ontario 10,851 24 0.2
Quebec 9,323 37 0.4
Atlantic 10,867 21 0.2
Total 10,714 22 0.2
Symptoms and ill-defined conditions British Columbia 6,427 97 1.5
Prairies 5,819 68 1.2
Ontario 6,666 123 1.9
Quebec 4,792 41 0.9
Atlantic 10,502 315 3.0
Total 6,291 104 1.7

Discussion

Eight percent of clinical diagnoses provided by office-based physicians resulted in an antimicrobial being recommended in 2011. Of these, 51% were for the treatment of diseases of the respiratory system, followed by 14% for infections of the urinary tract, and 11% for diseases of skin and subcutaneous tissue. Antimicrobial recommendations were highest for patients in the age groups of 0-2 years, 3-9 years, and 65 years or older. Antimicrobial recommendation rates decreased between 2007 and 2011 for diseases of the ear, the respiratory system, infections of the urinary tract, and diseases of the skin and subcutaneous tissue, while the rates for diseases of the genitourinary system remained stable.

Overall, the most commonly recommended antimicrobials included macrolides, penicillins with extended spectrum and fluoroquinolones. Provincial differences were observed in the antimicrobial recommendation rates and antimicrobial selected for treatment, with the Atlantic region and Québec having higher rates of antimicrobial recommendations compared to the national levels. British Columbia had the lowest rate of antimicrobial recommendations for diseases of the respiratory system, while Québec and the Atlantic region had the highest for diseases of the ear. The Prairies had the lowest rate of antimicrobial recommendations for infections of the urinary tract, but did observe an increase in these between 2010 and 2011. A similar rate of antimicrobial recommendations across the country was observed for diseases of the genitourinary system, while decreases in recommendations were observed across the country for diseases of the skin and subcutaneous tissue.

There are several limitations and caveats within the CDTI dataset. The drugs listed are those that the physician has written or recommended and do not represent actual prescriptions dispensed by pharmacists or products consumed by the patient, as information on patient compliance was not available. The data do not include patient visits to a primary care nurse, and diagnosis visits do not translate into number of patients as some patients may have visited multiple times for the same reason or were diagnosed with multiple diseases.

The appearance of a drug may include samples that do not necessarily tie to a prescription dispensed as physicians list all suggested treatments. Physicians also record drugs "previously ordered and continued" for the diagnosis, which would not necessarily tie to a prescription dispensed. In addition, some drug therapy and diagnosis is under-represented due to self-medication (i.e., over-the-counter products). Sample size is sometimes considered too small for decision making; however, these have been included for information purposes only and reliability of the data is dependent on sampling error, so caution should be taken when interpreting those disease categories with a small sample size. Data are only available at the regional level, where fluctuations may be more or less obvious and specific information for individual provinces could not be determined.

Antimicrobial resistance will continue to challenge the health of Canadians and those around the world for some time to come. Antibiotic use surveillance will help document the progress we have made in curbing it and the impact these changes might have had on overall antibiotic resistance.

Acknowledgements

The author would like to acknowledge the external reviewers of the Human Antimicrobial Use Report: Dr. John Conly, Dr. Jim Hutchinson, Dr. Warren McIsaac, Dr. David Patrick, Dr. Lynora Saxinger, Dr. Daniel Thirion, and Dr. Karl Weiss. Without their close collaboration and participation, the analysis and reporting of this data would not have been possible.

Conflict of interest

None.

Funding

This work was supported by the Public Health Agency of Canada.

Disclaimer

This article was prepared using data from IMS Health Canada Inc. The analyses, conclusions, opinions, and statements expressed are those of the authors and not those of IMS Health Canada Inc.

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