Weiss 2011.

Methods	Study design: ITS
Participants	Physicians, pharmacists Clinical speciality: general practice/family medicine Level of training: guidelines were distributed both to physicians and to residents in training, but prescribing data collected could only be from fully trained physicians Setting/country: outpatient (e.g. ambulatory care provided by hospitals/specialists)/Canada
Interventions	In 2004, the Quebec Medication Council (Conseil du Medicament du Quebec, Quebec City), with the help of designated physicians and pharmacists, issued a first series of guidelines targeting the most common infectious conditions in the outpatient setting. Eleven 2‐page highly graphic guidelines providing clinical information (diagnosis, investigation) and antibiotic recommendations were published and sent to all physicians (including medical residents), and pharmacists in January 2005. Emphasis was placed not only on proper antibiotic regimens but also on not using antibiotics when viral infections were suspected and on prescribing the shortest possible duration of treatment. A letter signed by all key stakeholders in Quebec (Minister of Health, College of Physicians, College of Pharmacists, and Medical associations) accompanied the initial mailing explaining the reasons supporting the process and the importance of prescribing antibiotics appropriately. The main objective of this study was to assess the impact of a multipronged, mostly Web‐based education strategy on the per capita number and cost of antibiotic prescriptions in the province of Quebec and to compare the trends with those the other 9 Canadian provinces
Outcomes	1 process outcome: monthly prescribing rates (number of prescriptions/1000 inhabitants) for all antibiotics in Quebec relative to the rest of Canada
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Intervention independent of other changes ‐ ITS	High risk	Quote, pg. 6: "this study has a number of limitations; we did not take into account samples given to physicians, but they represent a very small percentage of the total amount of antibiotics, and filling an antibiotic prescription at a community pharmacy does not guarantee that the patient will finish the entire treatment.  The Quebec antibiotic guidelines were produced in a period when health care professionals, government authorities, and perhaps the population as a whole were highly aware of the risks associated with antibiotic overuse (C. difficile infections). Thus, external factors besides the guidelines themselves may have influenced antibiotic prescribing practices"
Shape of Intervention effect pre‐specified ‐ ITS	Unclear risk	Quote, pg. 2: "the main objective of this study was to assess the impact of a multipronged, mostly Web‐based education strategy on the per capita number and  cost of antibiotic prescriptions in the province of Quebec and to compare the trends with those the other 9 Canadian provinces"
Intervention unlikely to affect data collection ‐ ITS	Low risk	The intervention (education guidelines) did not affect either the source or the method of data collection
Blinding of outcome assessors (detection bias) ‐ ITS All outcomes	Low risk	The outcome was objective
Incomplete outcome data (attrition bias) ‐ ITS All outcomes	Unclear risk	Quote, pg. 2: "the province of Quebec, Canada (2009 population, 7.8 million) has a universal health care insurance program in which medical visits, required investigations, and treatments (whether outpatient or inpatient) are provided free of charge to all citizens. In 1997, the Quebec government instituted a  universal drug plan in which everybody has to be covered by either private insurance obtained through his or her employer (57% of the population) or by the  public plan (43% of the population). Other provinces have similar drug plans, but not as extensive as that in Quebec"  COMMENT:  data for Quebec were likely to be complete, but no information was specified for the other provinces
Selective reporting (reporting bias) ‐ ITS	Low risk	All relevant outcomes in the methods section were reported in the results section
Other bias ‐ ITS	Low risk	There was no evidence of other risks of bias

4D: Der Deutsche Diabetes Dialyse Studie; 4S: Scandinavian Simvastatin Survival Study; ACC: American College of Cardiology; ACE: angiotensin‐converting enzyme; ACOG: American College of Obstetricians and Gynecologists; ACS: acute coronary syndrome; ADA: American Diabetes Association; AGREE: Appraisal of Guidelines for Research and Evaluation; AHA: American Heart Association; ALLHAT: Antihypertensive and Lipid‐Lowering Treatment to Prevent Heart Attack Trial; ANAES: Agence Nationale d'Accréditation et d'Evaluation en Santé; ASA: aspirin; ATP: Adult Treatment Panel; BP: blood pressure; CHD: coronary heart disease; CME: continuing medical education; C‐RCT: cluster randomised controlled trial; ERT: oestrogen replacement therapy; ES: effect size; GP: general practitioner; HERS: Heart and Estrogen/progestin Replacement Study; HOPE: Heart Outcomes and Prevention Evaluation; HRT: hormone replacement therapy; HT: hormone therapy; IBS: irritable bowel syndrome; ICU: intensive care unit; IHD: ischaemic heart disease; ITS: interrupted time series; IV: intravenous; LDL: low‐density lipoprotein; LIFE: Losartan Intervention for Endpoint; LMWH: low molecular weight heparin; MIRACL: Myocardial Ischemia Reduction with Acute Cholesterol Lowering; NDTI: National Disease and Therapeutic Index; NEJM: New England Journal of Medicine; NHS: National Health Service (UK); NICE: National Institute for Health and Clinical Excellence; NPA: National Prescription Audit Plus; NSAID: non‐steroidal anti‐inflammatory drug; ODB: Ontario's universal Drug Benefit program; PEM: printed educational material; PO: oral; PROVE IT‐TIMI22: Pravastatin or Atorvastatin Evaluation and Infection Therapy– Thrombolysis In Myocardial Infarction 22; RALES: Randomized Aldactone Evaluation Study; RCR: Royal College of Radiologists; RCT: randomised controlled trial; REVERSAL: Reversal of Atherosclerosis With Aggressive Lipid Lowering; SSRI: selective serotonin reuptake inhibitor; STEMI: ST‐elevation myocardial infarction; THR: total hip replacement; TKR: total knee replacement; UBH: United Behavioral Health; VA: Veterans Administration; VALUE: Valsartan Anti‐hypertensive Long‐term Use Evaluation; VBAC: vaginal births after caesarean; WHI: Women's Health Initiative.