Jeffrey A Johnson

University of Alberta, Edmonton, Alberta, Canada

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Publications (204)707.06 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The evidence on the association between pioglitazone use and bladder cancer is contradictory, with many studies subject to allocation bias. The aim of our study was to examine the effect of exposure to pioglitazone on bladder cancer risk internationally across several cohorts. The potential for allocation bias was minimised by focusing on the cumulative effect of pioglitazone as the primary endpoint using a time-dependent approach. Prescription, cancer and mortality data from people with type 2 diabetes were obtained from six populations across the world (British Columbia, Finland, Manchester, Rotterdam, Scotland and the UK Clinical Practice Research Datalink). A discrete time failure analysis using Poisson regression was applied separately to data from each centre to model the effect of cumulative drug exposure on bladder cancer incidence, with time-dependent adjustment for ever use of pioglitazone. These were then pooled using fixed and random effects meta-regression. Data were collated on 1.01 million persons over 5.9 million person-years. There were 3,248 cases of incident bladder cancer, with 117 exposed cases and a median follow-up duration of 4.0 to 7.4 years. Overall, there was no evidence for any association between cumulative exposure to pioglitazone and bladder cancer in men (rate ratio [RR] per 100 days of cumulative exposure, 1.01; 95% CI 0.97, 1.06) or women (RR 1.04; 95% CI 0.97, 1.11) after adjustment for age, calendar year, diabetes duration, smoking and any ever use of pioglitazone. No association was observed between rosiglitazone and bladder cancer in men (RR 1.01; 95% CI 0.98, 1.03) or women (RR 1.00; 95% CI 0.94, 1.07). The cumulative use of pioglitazone or rosiglitazone was not associated with the incidence of bladder cancer in this large, pooled multipopulation analysis.
    Diabetologia 12/2014; · 6.49 Impact Factor
  • Florence Y Lai, Jeffrey A Johnson, Doug Dover, Padma Kaul
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    ABSTRACT: Background We assessed the prevalence and pregnancy outcomes of preexisting diabetes mellitus (pre-DM) and gestational diabetes mellitus (GDM) in Alberta, Canada, 2005-2011.Methods We conducted a retrospective analysis of 327,198 singleton and 5,552 twin pregnancies resulting in live/still births in Alberta. We evaluated the odds ratios of adverse outcomes comparing pre-DM vs. no diabetes and GDM vs. no diabetes, controlling for maternal characteristics.ResultsDiabetes complicated 6.3% of pregnancies, with 88% being GDM. In singleton pregnancies, pre-DM and GDM were associated with increased risks of preeclampsia (adjusted odds ratio (aOR)=3.38 and 1.83, respectively), Caesarean delivery (aOR=2.53, 1.55), spontaneous preterm (aOR=4.20, 1.71) and labour-induced preterm (aOR=3.82, 2.00) in the mother; and macrosomia (aOR=2.11, 1.30), shoulder dystocia (aOR=1.54, 1.32), congenital anomalies (aOR=1.61, 1.20), and neonatal intensive care unit (NICU) admissions (aOR=3.81, 1.60) in the infants. In addition, pre-DM was associated with increased likelihood of stillbirth (aOR=3.73) and neonatal death (aOR=2.00), compared with non-diabetic pregnancies. In twin pregnancies, pre-DM was associated with increased risks of spontaneous (aOR=3.54) and labour-induced preterm births (aOR=3.57), large-for-gestational-age (LGA) infants (aOR=3.73), congenital anomalies (aOR=3.05) and NICU admissions (aOR=2.91). GDM was associated with increased risk of preeclampsia (aOR=1.54), Caesarean delivery (aOR=1.57) and LGA infants (aOR=1.63).Conclusions Pre-DM confers higher risks than GDM. Diabetes is associated with adverse outcomes in singleton and twin pregnancies, and the increased risks are generally similar or less in twins, probably due to their higher ‘baseline’ risks and closer clinical monitoring.
    Journal of Diabetes 12/2014; · 2.94 Impact Factor
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    ABSTRACT: The use of the interactive communication loop has been recommended as an effective method to enhance patient understanding and recall of information.
    Nursing research. 11/2014; 63(6):408-17.
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    ABSTRACT: This study aimed to describe the influence of social support on participants’ self-efficacy and motivation to perform physical activity before, during and after the Healthy Eating and Active Living for Diabetes in primary care networks (HEALD) programme.HEALD was a controlled trial of a 24-week primary care-based walking programme for people with type 2 diabetes, proven effective in increasing physical activity. Data used in this qualitative sub-study were derived from semi-structured interviews with purposefully selected HEALD completers (n = 13) six months after the programme ended. Qualitative data were analysed using content analysis.Prior to HEALD, participants reported feeling a lack of social support for diabetes management and fear of diabetes consequences. During the programme, they reported feeling supported by exercise specialists and peers in general and specifically to do physical activity; they reported weakening social support after HEALD ended. Accordingly, participants reported having self-efficacy and motivation to increase their physical activity during HEALD, but these did not persist after HEALD ended; many relapsed into former behaviours. Participants recommended a longer programme, with more contacts.Our findings are congruent with Social Cognitive Theory. Participants’ reported self-efficacy and motivation to adopt physical activity during HEALD were tied to feeling supported by the exercise specialists who led the programme and peers participating in the programme. However, these perceived improvements were compromised when social support was no longer available through HEALD. Periodic contacts with a health care provider post-programme may promote maintenance of positive behaviour changes following diabetes self-management programmes. Furthermore, an optimal mode of peer support requires study. Copyright © 2014 John Wiley & Sons, Ltd.
    Practical Diabetes. 11/2014; 31(9).
  • Jeffrey A Johnson
    Diabetologia 10/2014; · 6.49 Impact Factor
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    ABSTRACT: Background Guidelines and experts describe 5% to 10% reductions in body weight as `clinically important¿; however, it is not clear if 5% to 10% weight reductions correspond to clinically important improvements in health-related quality of life (HRQL). Our objective was to calculate the amount of weight loss required to attain established minimal clinically important differences (MCIDs) in HRQL, measured using three validated instruments.Methods Data from the Alberta Population-based Prospective Evaluation of Quality of Life Outcomes and Economic Impact of Bariatric Surgery (APPLES) study, a population-based, prospective Canadian cohort including 150 wait-listed, 200 medically managed and 150 surgically treated patients were examined. Two-year changes in weight and HRQL measures (Short-Form (SF)-12 physical (PCS; MCID¿=¿5) and mental (MCS; MCID¿=¿5) component summary score, EQ-5D Index (MCID¿=¿0.03) and Visual Analog Scale (VAS; MCID¿=¿10), Impact of Weight on Quality of Life (IWQOL)-Lite total score (MCID¿=¿12)) were calculated. Separate multivariable linear regression models were constructed within medically and surgically treated patients to determine if weight changes achieved HRQL MCIDs. Pooled analysis in all 500 patients was performed to estimate the weight reductions required to achieve the pre-defined MCID for each HRQL instrument.ResultsMean age was 43.7 (SD 9.6) years, 88% were women, 92% were white, and mean initial body mass index was 47.9 (SD 8.1) kg/m2. In surgically treated patients (two-year weight loss¿=¿16%), HRQL MCIDs were reached for all instruments except the SF-12 MCS. In medically managed patients (two-year weight loss¿=¿3%), MCIDs were attained in the EQ-index but not the other instruments. In all patients, percent weight reductions to achieve MCIDs were: 23% (95% confidence interval (CI): 17.5, 32.5) for PCS, 25% (17.5, 40.2) for MCS, 9% (6.2, 15.0) for EQ-Index, 23% (17.3, 36.1) for EQ-VAS, and 17% (14.1, 20.4) for IWQOL-Lite total score.Conclusions Weight reductions to achieve MCIDs for most HRQL instruments are markedly higher than the conventional threshold of 5% to 10%. Surgical, but not medical treatment, consistently led to clinically important improvements in HRQL over twoyears.Trial NCT00850356.
    BMC medicine. 10/2014; 12(1):175.
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    ABSTRACT: Depressive symptoms are common, and when coexisting with diabetes, worsen outcomes and increase health care costs. We evaluated a nurse case-manager-based collaborative primary care team model to improve depressive symptoms in diabetic patients.
    Diabetes care. 10/2014;
  • Canadian Journal of Diabetes 10/2014; 38(5, Supplement):S74. · 0.46 Impact Factor
  • Canadian Journal of Diabetes 10/2014; 38(5 Supplement):S26. · 0.46 Impact Factor
  • Diabetes care. 10/2014; 37(10):e221-2.
  • Canadian Journal of Diabetes 10/2014; 38(5, Supplement):S55. · 0.46 Impact Factor
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    ABSTRACT: Context: Observational studies report consistent associations between low vitamin D concentration and increased glycemia and risk of type 2 diabetes, but results of randomized controlled trials (RCTs) are mixed. Objective: To systematically review RCTs that report on the effects of vitamin D supplementation on glucose homeostasis or diabetes prevention. Data Sources: MEDLINE, EMBASE, SCOPUS, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Health Technology Assessment, and Science Citation Index from inception to June 2013. Study Selection: Trials that compared vitamin D3 supplementation with placebo or a non-vitamin D supplement in adults with normal glucose tolerance, prediabetes, or type 2 diabetes. Data Extraction and Synthesis: Two reviewers collected data and assessed trial quality using the Cochrane Risk of Bias tool. Random effects models were used to estimate mean differences (MD) and odds ratios (OR). The main outcomes of interest were HOMA-IR, HOMA-B, hemoglobin A1c levels, fasting blood glucose, incident diabetes, and adverse events. Data Synthesis: Thirty-five trials (43,407 patients) with variable risk of bias were included. Vitamin D had no significant effects on insulin resistance (HOMA-IR: MD, -0.04; 95%CI, -0.30 to 0.22, I(2)=45%), insulin secretion (HOMA-B: MD, 1.64; 95%CI, -25.94 to 29.22, I(2)=40%), or A1c (MD, -0.05%; 95%CI, -0.12 to 0.03, I(2)=55%) compared with controls. Four RCTs reported on progression to new diabetes and found no effect of vitamin D (OR, 1.02; 95%CI, 0.94 to 1.10, I(2)=0%). Adverse events were rare, and there was no evidence of publication bias. Conclusions: Evidence from available trials shows no effect of vitamin D3 supplementation on glucose homeostasis or diabetes prevention. Definitive conclusions may be limited in the context of the moderate degree of heterogeneity, variable risk of bias, and short-term follow-up duration of the available evidence to date.
    The Journal of clinical endocrinology and metabolism. 07/2014;
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    ABSTRACT: Obesity is a pressing public health concern, which frequently presents in primary care. With the explosive obesity epidemic, there is an urgent need to maximize effective management in primary care. The 5As of Obesity ManagementTM (5As) are a collection of knowledge tools developed by the Canadian Obesity Network. Low rates of obesity management visits in primary care suggest provider behaviour may be an important variable. The goal of the present study is to increase frequency and quality of obesity management in primary care using the 5As Team (5AsT) intervention to change provider behaviour.Methods/design: The 5AsT trial is a theoretically informed, pragmatic randomized controlled trial with mixed methods evaluation. Clinic-based multidisciplinary teams (RN/NP, mental health, dietitians) will be randomized to control or the 5AsT intervention group, to participate in biweekly learning collaborative sessions supported by internal and external practice facilitation. The learning collaborative content addresses provider-identified barriers to effective obesity management in primary care. Evidence-based shared decision making tools will be co-developed and iteratively tested by practitioners. Evaluation will be informed by the RE-AIM framework. The primary outcome measure, to which participants are blinded, is number of weight management visits/full-time equivalent (FTE) position. Patient-level outcomes will also be assessed, through a longitudinal cohort study of patients from randomized practices. Patient outcomes include clinical (e.g., body mass index [BMI], blood pressure), health-related quality of life (SF-12, EQ5D), and satisfaction with care. Qualitative data collected from providers and patients will be evaluated using thematic analysis to understand the context, implementation and effectiveness of the 5AsT program.
    Implementation Science 06/2014; 9(1):78. · 2.37 Impact Factor
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    ABSTRACT: Studies comparing the measurement properties of EQ-5D 3L (3L) and EQ-5D 5L (5L) are limited to specific patient populations with small sample sizes. Using a general population sample, we compared 3L and 5L in terms of their measurement properties and association with number of chronic conditions, including multimorbidity - the concurrent occurrence of two or more chronic conditions.
    Health and Quality of Life Outcomes 05/2014; 12(1):74. · 2.27 Impact Factor
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    ABSTRACT: The purpose of this study was to assess the relationship between diabetic ketoacidosis (DKA) hospitalization and driving distance from home to outpatient diabetes care in adults with type 1 diabetes mellitus. We identified adults with type 1 diabetes using clinical and administrative databases living in Calgary, Alberta. The International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, codes were used to identify DKA hospitalizations, and geographic information systems were used to obtain road distance. Multivariate logistic regression was used to assess the association between driving distance (exposure) to diabetes care sites and the outcome of DKA hospitalization. We identified 1467 patients (151 patients with DKA) with type 1 diabetes. Patients with DKA hospitalizations were younger (35.6 vs. 41.0 years), had shorter duration of diabetes (13.6 vs. 18.7 years) and higher glycated hemoglobin (9.2% vs. 8.4%). Driving distance from home to diabetes centre 1 (adjusted odds ratio 1.02 per 1 km; 95% confidence interval, 0.96 to 1.07), diabetes centre 2 (adjusted odds ratio 1.01; 95% confidence interval, 0.99 to 1.04) or closest general practitioner (adjusted odds ratio 0.9; 95% confidence interval, 0.63 to 1.25) was not associated with DKA hospitalization. Driving distance was also not associated with glycemic control. Within a large urban city, driving distance to diabetes centres does not appear to be protective of DKA hospitalization. However, this work does not preclude the role of local travel distance and diabetes outcomes. More research is required to explore the role of other individual, neighbourhood and community factors that influence DKA hospitalization.
    Canadian Journal of Diabetes 05/2014; · 0.46 Impact Factor
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    ABSTRACT: The aim of this work was to compare the incidence of illness attributable to influenza in working-age adults (age <65 years) with and without diabetes. We performed a cohort study using administrative data from Manitoba, Canada, between 2000 and 2008. All working-age adults with diabetes were identified and matched with up to two non-diabetic controls. We analysed the rates of influenza-like illness physician visits and hospitalisations, pneumonia and influenza hospitalisations, and all-cause hospitalisations. Multivariable regressions were used to estimate the influenza-attributable rate of each outcome. We included 745,777 person-years of follow-up among 166,715 subjects. The median age was 50-51 years and 48-49% were women; adults with diabetes had more comorbidities and were more likely to be vaccinated for influenza than those without diabetes. Compared with similar adults without diabetes, those with diabetes had a 6% greater (RR 1.06, 95% CI 1.02, 1.10; absolute risk difference 6 per 1,000 adults per year) increase in all-cause hospitalisations associated with influenza, representing a total of 54 additional hospitalisations. There were no differences in the influenza-attributable rates of influenza-like illness (p = 0.06) or pneumonia and influenza (p = 0.11). Guidelines calling for influenza vaccinations in diabetic, in addition to elderly, adults implicitly single out working-age adults with diabetes. The evidence supporting such guidelines has hitherto been scant. We found that working-age adults with diabetes appear more susceptible to serious influenza-attributable illness. These findings represent the strongest available evidence for targeting diabetes as an indication for influenza vaccination, irrespective of age.
    Diabetologia 02/2014; · 6.49 Impact Factor
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    ABSTRACT: Aims Many studies have demonstrated the effectiveness of primary prevention strategies in type 2 diabetes, however, questions remain around the feasibility of high resource, intensive interventions within a healthcare setting. We report the results of a dietitian-led pre-diabetes education session targeting healthy eating and active living as strategies for weight reduction. Methods Participants were asked to complete a baseline questionnaire prior to completing the pre-diabetes education session and were sent follow-up questionnaires at 3 and 6 months. Differences between participants at baseline, 3 and 6 months were determined using χ2, t-tests and ANOVA. Results Of the 211 participants asked to fill out baseline questionnaires, 45 participants completed questionnaires at baseline, 3 months and 6 months. Although we observed general trends towards improvements in diet, physical activity and weight related behaviours among the 45 completers, no significant changes were observed among participants between questionnaire periods. Conclusion A “one-off”, theory-guided group education session may be insufficient to support lifestyle modifications in the context of weight management in a pre-diabetic population. Further evaluation of the efficacy and feasibility of the PCN as a setting for lifestyle intervention is required.
    Primary Care Diabetes. 02/2014;
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    ABSTRACT: To explore the relationship between health promotion counseling (HPC) provided by FPs and health-related quality of life (HRQL) and the use of health care services among patients with chronic conditions, while assessing the effect of mental health on these relationships. Telephone survey using random-digit dialing. Alberta. A total of 1615 participants with chronic conditions. Health promotion counseling provided by FPs, which was assessed using 4 questions; HRQL using the Euro quality of life 5-dimensions (EQ-5D) questionnaire; and the use of health care services assessed with self-reported emergency department (ED) visits and hospitalizations. Of the 1615 participants with chronic conditions, 55% were female and more than two-thirds were older than age 45 years. Less than two-thirds of participants received HPC from their FPs. In patients without anxiety or depression, those who needed help from their FPs in making changes to prevent illness had a 0.05 lower EQ-5D score than those who did not (P < .001); and those who received diet counseling had a 0.03 higher EQ-5D score than their counterparts did (P = .048). However, these associations were not observed in patients with anxiety or depression. Patients were more likely to have visited EDs if they needed their physicians' help in making changes to prevent illness (odds ratio 1.43, 95% CI 1.08 to 1.89) and less likely to visit EDs if they had been encouraged by their physicians to talk about their health concerns (odds ratio 0.69, 95% CI 0.52 to 0.91). None of the HPC items was associated with hospitalizations. Not all patients with chronic conditions are receiving HPC from their FPs. Also, there is an association between HPC and important health outcomes (ie, HRQL and ED visits), but this association is not apparent for those with anxiety or depression.
    Canadian family physician Medecin de famille canadien 02/2014; 60(2):e113-20. · 1.19 Impact Factor
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    ABSTRACT: Objective: To characterize health-related quality of life (HRQL) impairment in severely obese subjects, using several validated instruments. Design and Methods: A cross-sectional analysis of 500 severely obese subjects was completed. Short-Form (SF)-12 [Physical (PCS) and Mental (MCS) component summary scores], EuroQol (EQ)-5D [Index and Visual Analog Scale (VAS)], and Impact of Weight on Quality of Life (IWQOL)-Lite were administered. Multivariable linear regression models were performed to identify independent predictors of HRQL. Results: Increasing BMI was associated with lower PCS (-1.33 points per 5 kg/m(2) heavier; p < 0.001), EQ-index (-0.02; p < 0.001), EQ-VAS (-1.71; p = 0.003) and IWQOL-Lite (-3.72; p = 0.002), but not MCS (p = 0.69). The strongest predictors (all p < 0.005) for impairment in each instrument were: fibromyalgia for PCS (-5.84 points), depression for MCS (-7.49 points), stroke for EQ-index (-0.17), less than full-time employment for EQ-VAS (-7.06), and coronary disease for IWQOL-Lite (-10.86 points). Chronic pain, depression, and sleep apnea were associated with reduced HRQL using all instruments. Conclusion: The clinical impact of BMI on physical and general HRQL was small, and mental health scores were not associated with BMI. Chronic pain, depression, and sleep apnea were consistently associated with lower HRQL.
    Obesity 01/2014; · 3.92 Impact Factor
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    ABSTRACT: The Alberta Project Promoting active Living and healthy Eating in Schools (APPLE Schools) is a comprehensive school health program that is proven feasible and effective in preventing obesity among school aged children. To support decision making on expanding this program, evidence on its long-term health and economic impacts is particularly critical. In the present study we estimate the life course impact of the APPLE Schools programs in terms of future body weights and avoided health care costs.
    PLoS ONE 01/2014; 9(7):e102242. · 3.53 Impact Factor

Publication Stats

5k Citations
707.06 Total Impact Points


  • 1997–2014
    • University of Alberta
      • • School of Public Health
      • • Department of Public Health Sciences
      • • Department of Medicine
      • • Department of Surgery
      • • Faculty of Medicine and Dentistry
      • • Faculty of Pharmacy and Pharmaceutical Sciences
      Edmonton, Alberta, Canada
  • 2013
    • TEC Edmonton
      Edmonton, Alberta, Canada
    • Memorial University of Newfoundland
      St. John's, Newfoundland and Labrador, Canada
  • 2010–2013
    • Statistics Canada
      • Division of Health Analysis
      Ottawa, Ontario, Canada
  • 2012
    • Athabasca University
      • Centre for Nursing and Health Studies
      Athabasca, Alberta, Canada
  • 2010–2012
    • The University of Calgary
      • • Faculty of Medicine
      • • Faculty of Education
      Calgary, Alberta, Canada
  • 2007–2009
    • University of Illinois at Chicago
      • • Center for Pharmacoeconomic Research
      • • Department of Pharmacy Administration
      Chicago, IL, United States
    • National University of Singapore
      • Centre for Health Services Research
      Singapore, Singapore
    • Canadian Agency for Drugs and Technologies in Health
      Ottawa, Ontario, Canada
  • 2008
    • Oxford Outcomes
      Oxford, England, United Kingdom
  • 2003–2008
    • Institute of Health Economics
      Edmonton, Alberta, Canada
  • 2005
    • National Cancer Institute (USA)
      • Division of Cancer Control and Population Sciences
      Bethesda, MD, United States
    • The University of Western Ontario
      • Department of Medicine
      London, Ontario, Canada
    • QualityMetric
      Providence, Rhode Island, United States