A research report submitted to the faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Science in Medicine in Anaesthesiology Johannesburg, 2017 / Background Adverse events and errors are a widespread cause of morbidity and mortality in the health care environment. Adverse event and error reporting systems have been shown to potentially reduce the occurrence of these events, however there is still significant underreporting. Little is known regarding the barriers to reporting of adverse events and errors in the context of South Africa, or what emotional and attitudinal barriers may be present regarding a formal reporting system amongst anaesthetists in the Department of Anaesthesiology at the University of the Witwatersrand. Methods A prospective, descriptive, contextual study design utilizing an anonymous self-administered questionnaire was distributed to 133 anaesthetists who attended academic anaesthetic meetings. Results One hundred and eighteen questionnaires met the criteria for analysis, giving a response rate of 92%. Barriers to reporting included a “code of silence” in medicine and blame from colleagues. If a specified error as opposed to an adverse event had occurred, participants were more likely to agree with barriers regarding fear of litigation, disciplinary action, getting into trouble, as well as colleagues that may be unsupportive. Strategies to promote reporting of adverse events and errors include senior role models who encourage reporting and individualised feedback regarding reports made. Conclusions Most anaesthetists in our study disagreed with barriers to reporting an unspecified adverse event. However, if an error has occurred, reporting behaviour may be inhibited by barriers regarding fears of litigation, disciplinary action and lack of support. Senior role models that openly support reporting along with individualised feedback may increase reporting rates. / MT2017

Objective: Today, many healthcare organizations have implemented health care reporting systems in the hope of learning from experience to prevent or reduce adverse events, medical errors or accidents. However, most applications have failed or not been implemented as predicted. This study presents an extended technology acceptance model (TAM) that integrates subjective norm, trust, and management support into the TAM to investigate what determines healthcare professional reporting system acceptance. Design: The proposed model was empirically tested using data collected from a survey in the hospital environment. The structural equation modeling technique was used to evaluate the causal model and confirmatory factor analysis was performed to examine the reliability and validity of the measurement model. Measurements: Questionnaire administered items measuring the behavioral intention to use the reporting system and five hypothesized antecedents. Results: Our findings indicated that all variables significantly affected healthcare professionals¡¦ behavioral intention to use the reporting system. Among them, the subjective norm had the most significant influence. Conclusion: The proposed model provides a means to understand what factors determine healthcare professional¡¦s behavioral intention to use a reporting system and how this may affect future use. In addition, antecedents to the behavioral intent can be used to predict reporting system acceptance in advance of system development.

Comparison of Post-licensure safety surveillance of 13-Valent Pneumococcal Conjugate vaccine and 7-Valent Pneumococcal Conjugate vaccine: Data from the Vaccine Adverse Event Reporting System (VAERS). Background: On February 24, 2010, Food and Drug Administration (FDA) licensed a 13-valent pneumococcal conjugate vaccine (Prevnar 13®, [PCV13]) for use among children aged 6 weeks--71 months. The Advisory Committee on Immunization Practices (ACIP) recommended PCV13 routine vaccination of all children aged 2--59 months, children aged 60--71 months with underlying medical conditions, with PCV13 replacing PCV7 for all doses. Methods: We searched case reports to the Vaccine Adverse Event Reporting System (VAERS), a US passive surveillance system, for adverse events (AEs) reported after immunization with PCV13 vaccine from February 24, 2010 through February 24, 2011 for persons vaccinated from February 24, 2010 through December 31, 2010 and compared them with AEs reported by persons who were vaccinated with PCV7. Results: VAERS received 1503 reports of AEs after PCV13; multiple vaccines were given in 79.0% of reports. One hundred eighty (11.9%) were coded as serious, including nineteen reports of death. The most frequently reported symptoms were injection site reactions, fever, irritability and vomiting. Seven hundred fifty-eight (50.4%) reports comprised males. Most reports (37.7%) were from children 1-2 years. Total number of reports received for PCV13 was very similar to those received after vaccination with PCV7. Conclusions: AEs reported to VAERS following 13-valent pneumococcal conjugate vaccine were consistent with AEs previously observed in pre-licensure trials. We did not identify any major safety concerns or outcomes.

Introduction. The high cost and concern of adverse events, particularly infections, limit the use of biologic disease-modifying anti-rheumatic (bDMARD) therapies. We undertook this retrospective study to document their use for immune-mediated diseases (IMDs) and explore the efficacy, safety, adherence and screening practices prior to initiating bDMARDs in a tertiary referral hospital. Methods. A folder review of all adult and paediatric patients treated for IMDs with bDMARDs at Groote Schuur and Red Cross Hospitals between January 2013 and December 2019. Clinico-demographic particulars, details of bDMARD therapy, and adverse events were collated. Changes in disease activity were measured by diseasespecific tools at 6, 12, 24-months and at the last available visit, and patient adherence to bDMARDs was explored by folder and pharmacy record review. Results. We studied 151 folders, with 182 bDMARDs uses (29 patients used more than 1 bDMARD). Patients were from rheumatology (n= 38: 13 rheumatoid arthritis; 10 spondyloarthritis, 5 Systemic Lupus Erythematosus (SLE) , 5 inflammatory myositis and 5 other conditions); gastroenterology (n=31; 26 Crohn`s and 5 Ulcerative Colitis), dermatology (n=9; psoriasis), neurology (n=4, ophthalmology (n= 25; 6 scleritis, 18 uveitis, 1 optic neuritis), and paediatrics (n= 45, 26 juvenile idiopathic arthritis , 12 SLE, 7 other conditions). The bDMARDs used were TNF inhibitors (112), rituximab (55), tocilizumab (10), anakinra (3), abatacept (1), and tofacitinib (1). The vast majority of patients had an excellent response and were in low disease activity or remission at their last available visit. Adverse events included severe infection (4), tuberculosis (TB) (2), mild infection (4), severe allergic reaction (3), mild skin reaction (14), elevated liver enzymes (2), and worsening interstitial lung disease ILD (1). bDMARD Therapy was discontinued in 18 patients, most commonly due to adverse reaction (9), lack of response (3), poor adherence (2), or remission (1). bDMARD Therapy was changed to alternative therapy in 29 patients, most commonly because of poor response (14), or adverse effects (9) or poor adherence (3). Poor adherence or patients lost to follow-up was noted in 18/182 (9.9%). Complete latent TB infection screening with chest x-ray and TB skin test was performed in only 55 (36.4 %) but INH prophylaxis was given to 51/88 (57.9%) of patients prescribed TNFi therapy. Hepatitis B screening performed in 93 (61.6 %) patients, but most patients (72.2 %) were not tested for Hepatitis B core ab. Hepatitis C screening was performed in 81 (53.6 %) patients. Only 88 (58.3%) patients had a recent HIV test. The majority (17.2%) received the influenza vaccine, but only 24 (15.8 %) received pneumococcal vaccination. Discussion and Conclusion. bDMARD therapy was an effective treatment, and the most common adverse effect was infection (7.2%), with 2 TB infections. Vaccination and screening for TB, viral hepatitis and HIV was suboptimal. Of concern, poor adherence to bDMARDs was frequently encountered.

Throughout the past several decades, research regarding counselor resilience has shifted from a pathology-based to a strengths-based approach. As a result, researchers have moved away from primarily identifying risk factors and now focus on protective factors. Researchers have found that social supports serve as a protective factor in counselor resilience. However, there is a lack of understanding of how counselors receive that social support, specifically after a professional adverse event. Professional adverse events are common given the nature of counseling work. For example, undesirable occurrences such as client suicide, attempted suicide, life threatening illnesses, accidents, overdose, or loss of a child are considered professional adverse events. This study explored how ten professional counselors experienced social support following professional adverse events. Three themes emerged from these counselors' stories: difficulty seeking support, misplaced support, and acts of kindness. Implications for counselors include honoring both confidentiality and their own humanness, the cultivating co-regulating relationships, and reinforcing acts of kindness. Counselor educators and supervisors can foster counselor resilience by using the implications to teach counselors how to invite effective social support. / Doctor of Philosophy / Being a counselor can be both challenging and rewarding. Given the heavy caseloads and complexity of cases, it is common for counselors to experience adverse professional events. Research shows that protective factors serve as a buffer against stress. Social support is a protective factor that assists counselors in maintaining wellness and building resiliency. This study explored how professional counselors received support from interpersonal relationships following a professional adverse event. Findings from this study indicate the importance of counselors honoring their own humanness while protecting the client’s confidentiality, the importance of having co-regulating relationships, and the healing power of acts of kindness.

Health information technology has been widely accepted as having the potential to decrease the prevalence of adverse events and improve workflows and communication between healthcare workers. However, the emergence of health technologies has introduced a new type of medical error. Technology-induced errors are a type of medical error that can result from the use of health information technology in all stages of the health information systems life cycle. The purpose of this study is to identify what types of technology-induced errors are present in the key health information technology vendors in the United States, determine if there are any similarities and differences in technology-induced errors present among the key health information technology vendors in the United States, and determine what methods are utilized, if any, by the key vendors of health information technologies to address and/or resolve reported technology-induced errors. This study found that the most commonly reported technology-induced errors are those related to unexpected system behaviours, either through their direct use or through the communication between systems. It was also found that there is a large difference in the number of adverse events being reported by the key health information technology vendors. Just three vendors represent 85% of the adverse events included in this study. Finally, this study found that there are vendors who are posting responses to reported technology-induced errors and these vendors are most commonly following up with software updates and notifications of safety incidents. This study highlights the importance of analyzing adverse event reports in order to understand the types of technology-induced errors that are present in health information technology. / Graduate

Thesis advisor: Callista Roy / Problem: Nurses act as safety nets, protecting patients from harm through the identification, interruption and recovery of medical errors and adverse events but we need to know more about ways to learn from safety events. This study aimed to address a gap in our understanding of how the PRISM Program affects nurses’ attitudes of safety culture, awareness of the recovery of medical errors, and practice as they relate to patient safety and error prevention. Participants: Critical care nurses in a large academic hospital from intervention (n=95) and control (n=90) units were surveyed pre and post-implementation of the PRISM Program. Intervention unit nurse response rates were 46% pre-survey and 41% post-survey. Control unit nurses' response rates were 38% for pre-survey and 31% for post-survey responses. A total of 42 (44%) intervention unit nurses participated in the PRISM Program. Methods: A pre/post-test design with an intervention and control unit was used to evaluate the effects of the PRISM Program on nurses’ responses on the Safety Attitude Questionnaire (SAQ) and the Recovery of Medical Error Inventory (RMEI) over a three month period. Nurses responded to questions about the impact on their practice. Findings: Analysis demonstrated a significant decrease in the SAQ working conditions post-survey subscale scores and significant findings in the main effects, decreased SAQ subscales: teamwork, job satisfaction, safety climate and perceptions of hospital management. The RMEI did not produce any significant findings. Comments provided insight into some nurses’ participation in the program and the impact on their practice. Implications: A significant decrease in post-survey scores indicate that informed nurses had a more critical view of safety culture and the environment they work in. Nurses expressed a desire to further use surveillance and additional manual checks that placed increased accountability and responsibility for their role in using strategies to keep patient safe and prevent errors and patient harm. / Thesis (PhD) — Boston College, 2017. / Submitted to: Boston College. Connell School of Nursing. / Discipline: Nursing.

Introdução: A varfarina é um dos anticoagulantes orais (ACO) mais utilizados na atenção primária a saúde. Com janela terapêutica estreita, exibe grande variabilidade de resposta farmacológica, e maior suscetibilidade de eventos adversos, como sangramentos e tromboembolismo venoso. Entre os fatores que influenciam na variabilidade de dose destaca-se as interações tanto com medicamentos, como com a dieta e o polimorfismo genético. Objetivos: Estimar a incidência de eventos adversos relacionados ao uso de varfarina e descrever o itinerário do usuário pelo sistema público de saúde para resolução dos problemas. Métodos: trata-se de uma coorte prospectiva realizada por um período de 18 meses com usuários do serviço público de saúde, em uso de varfarina, do município de Ijuí/RS. Os dados foram coletados por entrevistas mensais nas residências e complementados com informações médicas obtidas na atenção primária e terciária. As interações medicamentosas foram checadas em bases de dados e os hábitos alimentares conforme metodologia validada. A estatística utilizada para associar sangramento e Time in Therapeutic Range (TTR) e os fatores de risco foi teste de Poison. O projeto foi aprovado no Comitê de Ética em Pesquisa da UFRGS, com parecer número 336.259/2013. Resultados: Foram entrevistados e acompanhados 69 pacientes, sendo que 64 concluíram o acompanhamento e 5 faleceram durante o estudo, 55,1% eram do sexo feminino, com idade média de 64,3 ±13,7 anos. O tempo médio de uso de varfarina foi de 5,5 anos, a dose média semanal foi de 30,69±15,19mg e o principal motivo para uso de varfarina foi prótese valvular (39,7%). A média de medicamentos utilizados por usuário foi de 9,6±4,5. Quanto aos eventos, os sangramentos tiveram incidência de 37,7/100 pacientes/ano, o tromboembolismo de 4,8/100 pacientes/ano e de óbitos de 4,8/100 pacientes/ano. Os sangramentos apresentaram associação com possuir mais que três interações medicamentosas com a varfarina (p=0,048) e com uso de medicamentos por automedicação (p=0,030). Já para o TTR houve associação com a idade inferior a 65 anos (p=0,032). E 67 usuários estavam suscetíveis a interações medicamentosasas com varfarina, com predomínio das moderadas, sendo a média de interações com este medicamento de 2,91±1,52. A maioria das interações agiam sobre o efeito anticoagulante da varfarina, aumentando a probabilidade de sangramento. Entre as interações que os usuários apresentavam, no momento do sangramento, as mais frequentes foram com: omeprazol, sinvastatina e paracetamol. A maioria dos entrevistados apresentou consumo baixo de vitamina K. Verificou-se que sangramentos e tromboembolismos venosos foram mais frequentes nos pacientes em início de tratamento. E todos os pacientes que foram a óbito durante o acompanhamento (5) eram pacientes com mais de um ano de uso de varfarina. Para a resolução de eventos adversos na maioria dos casos o paciente realizou cuidado domiciliar (53,4%), seguido por busca pela Unidades Básicas de Saúde, 7 pacientes buscaram o serviço de emergência e 5 realizaram internação hospitalar. Observou-se que aproximadamente metade dos pacientes não mostrou seus exames de INR (Razão Normalizada Internacional) ao médico. E na falta de varfarina na rede pública de saúde do município, que ocorreu entre os meses 13 e 16, entre 24,9 a 43,5%, deixaram de usar o medicamento. Os resultados do polimorfismo demonstram que 47 (71,2%) não apresentam polimorfismo ao genótipo CYP2C9, e 24 (36,4%) ao genótipo VKORC1. Avaliando os dois genótipos associados, verifica-se que 17 (25,8%) não apresentam polimorfismo a nenhum destes. Não foi observada associação estatística do polimorfismo com sexo e raça. Observou-se diferença significativa entre a dose utilizada para os diferentes polimorfismos (p=0,013). Da mesma forma, para o VKORC1, houve diferença significativa entre a dose e o genótipo (p=0,018). Conclusão: Estes resultados demonstram a necessidade de uma maior assistência a estes pacientes, buscando melhores resultados clínicos, com menos eventos adversos. / Introduction: Warfarin is an oral anticoagulant (OAC) most used in primary health care. With narrow therapeutic window, shows great variability in drug response, and greater susceptibility to adverse events such as bleeding and venous thromboembolism. Among the factors that influence the amount of variability highlights the interactions with both drugs, as with diet and genetic polymorphism. Objectives: To estimate the incidence of adverse events related to warfarin use and describe the user journey through the public health system to the problems. Methods: This is a prospective cohort study conducted over a period of 18 months with users of the public health service in the use of warfarin, the city of Ijuí/RS. The data were collected monthly interviews in homes and complemented with medical information obtained in primary and tertiary care. Drug interactions were checked in databases and eating habits as validated methodology. The statistics used to associate bleeding and Time in Therapeutic Range (TTR) and the risk factors was Poison test. The project was approved by the Research Ethics Committee of UFRGS, with opinion number 336259/2013. Results: We interviewed and followed 69 patients, 64 completed the follow-up and 5 died during the study, 55.1% were female, mean age 64.3 ± 13.7 years. The mean duration of warfarin use was 5.5 years, the average weekly dose was 30.69 ± 15,19mg and the main reason for warfarin use was valvular prosthesis (39.7%). The average per user used medications was 9.6 ± 4.5. As for events, the bleeding had incidence of 37.7 / 100 patients / year, thromboembolism of 4.8 / 100 patients / year and deaths of 4.8 / 100 patients / year. Bleeds were associated with having more than three drug interactions with warfarin (p = 0.048) and use of self-medication by drugs (p = 0.030). As for the TTR was no association with age less than 65 years (p = 0.032). And 67 users were susceptible to medicamentosasas interactions with warfarin, with a predominance of moderate, with an average of interactions with this drug of 2.91 ± 1.52. Most interactions acting on the anticoagulant effect of warfarin, increasing the probability of bleeding. Among the interactions that users had, at the time of bleeding, the most common were with: omeprazole, simvastatin and acetaminophen. Most respondents showed low consumption of vitamin K. It was found that bleeding and venous thromboembolism were more frequent in patients starting treatment. And all patients who died during follow-up (5) were patients with more than one year of warfarin use. For adverse event resolution in most cases the patient underwent home care (53.4%), followed by search for the Basic Health Units, 7 patients sought emergency services and 5 held hospitalization. It was observed that approximately half of the patients showed their INR test (International Normalized Ratio) to the doctor. And in the absence of warfarin in public municipal health, which occurred between the months 13:16, from 24.9 to 43.5% stopped using the drug. The polymorphism results demonstrate that 47 (71.2%) did not have the polymorphism CYP2C9 genotype, and 24 (36.4%) the VKORC1 genotype. Evaluating the two genotypes associated, it is found that 17 (25.8%) did not show any polymorphism thereof. There was no statistical association of the polymorphism with gender and race. A significant difference between the dose for different polymorphisms (p = 0.013). Likewise, for the VKORC1, a significant difference between the dose and genotype (p = 0.018). Conclusion: These results demonstrate the need for further assistance to these patients, looking for better clinical outcomes, with fewer adverse events.

SAMMANFATTNING Sjuksköterskan tillämpar omvårdnadsprocessen genom att observera, värdera, prioritera, dokumentera och vid behov åtgärda och hantera förändringar i allmäntillståndet, samt motverka komplikationer i samband med sjukdom, vård och behandling. Andningsfrekvens (AF) är den vitalparameter som först förändras och signalerar en förändring i allmäntillståndet. Vid de flesta hjärtstopp på sjukhus finns tecken till försämring hos patienten redan några timmar eller upp till ett dygn före.  Syftet var att undersöka sjuksköterskans inställning och följsamhet till att mäta och bedöma AF hos akuta sjuka patienter, för att tidigt upptäcka en försämring i patientens hälsotillstånd. Genom en litteraturstudie framkom fyra teman. Rutiners betydelse, sjuksköterskans inställning till AF och varför den inte mättes, värdet av förändringsarbete samt möjliga arbetssätt för att undvika vårdskador. Rutiner för mätning av AF, olika poängsystem och mätmallar för bedömning av vitalparametrar, påverkade antalet mätningar och registreringar av AF. Den enskilda sjuksköterskans inställning inverkade på mätningen och bedömningen av AF. Flera anledningar till varför AF inte mättes fanns. Studier visade att förändringsarbete och implementering av nya arbetssätt var ett komplext område, insatser krävdes inom flera områden på olika nivåer. Vårdskador och plötslig oväntad död minskade när nya rutiner och arbetssätt kombinerades med utbildning, uppföljning och återkoppling till personalen. AF är en viktig vitalparameter. Används inte den kunskapen för att hitta patienter på väg att försämras, riskerar patienterna att drabbas av vårdskador. Ett utbildningsbehov finns, den senaste forskningen har påvisat att rätt genomförd implementering av övervakningsrutiner och förändrat arbetssätt kan ge ett bra utfall i minskat antal vårdskador och oförutsedd död. / ABSTRACT The nurse applies the nursing process by observing, evaluating, prioritising, documenting and when necessary manage changes in the condition of the patient, and to prevent complications associated with disease, care and treatment. Respiratory Rate (RR) is the vital sign that first changes and signals changes in a patient’s condition. In most cardiac arrests there are signs of deterioration of the patient a few hours up to a day before the event.    The aim of this study was to investigate the nurse´s attitude and adherence to measure and assess RR in acutely ill patients, for an early detection of deterioration in the patient's state of health. Through a literature study four themes were emerged. The importance of guidelines, the nurses' attitude and why the RR was not measured, the value of change of management and possible ways to avoid injuries. Guidelines for the measurement of RR, different scoring systems and observations charts for the assessment of vital signs all affected the measuring and scorings of RR. The individual nurse's attitude affected the measurement and assessment of RR. Several reasons why RR was not measured were found. The studies showed that the process of change and implementation of new ways of working is a complex, and efforts were needed in several areas and at different levels. Care injuries and sudden unexpected deaths decreased when new routines and working procedures were combined with training, monitoring and feedback to the staff.   Research shows that RR is an important vital sign. If this knowledge is not used to find patients about to deteriorate, these patients risk suffering from permanent health effects. There is a need for significant training in this area and recent research has shown that a correct implementation of the procedures provide a good outcome in a decreased number of medical injuries and unexpected death

Introdução: A varfarina é um dos anticoagulantes orais (ACO) mais utilizados na atenção primária a saúde. Com janela terapêutica estreita, exibe grande variabilidade de resposta farmacológica, e maior suscetibilidade de eventos adversos, como sangramentos e tromboembolismo venoso. Entre os fatores que influenciam na variabilidade de dose destaca-se as interações tanto com medicamentos, como com a dieta e o polimorfismo genético. Objetivos: Estimar a incidência de eventos adversos relacionados ao uso de varfarina e descrever o itinerário do usuário pelo sistema público de saúde para resolução dos problemas. Métodos: trata-se de uma coorte prospectiva realizada por um período de 18 meses com usuários do serviço público de saúde, em uso de varfarina, do município de Ijuí/RS. Os dados foram coletados por entrevistas mensais nas residências e complementados com informações médicas obtidas na atenção primária e terciária. As interações medicamentosas foram checadas em bases de dados e os hábitos alimentares conforme metodologia validada. A estatística utilizada para associar sangramento e Time in Therapeutic Range (TTR) e os fatores de risco foi teste de Poison. O projeto foi aprovado no Comitê de Ética em Pesquisa da UFRGS, com parecer número 336.259/2013. Resultados: Foram entrevistados e acompanhados 69 pacientes, sendo que 64 concluíram o acompanhamento e 5 faleceram durante o estudo, 55,1% eram do sexo feminino, com idade média de 64,3 ±13,7 anos. O tempo médio de uso de varfarina foi de 5,5 anos, a dose média semanal foi de 30,69±15,19mg e o principal motivo para uso de varfarina foi prótese valvular (39,7%). A média de medicamentos utilizados por usuário foi de 9,6±4,5. Quanto aos eventos, os sangramentos tiveram incidência de 37,7/100 pacientes/ano, o tromboembolismo de 4,8/100 pacientes/ano e de óbitos de 4,8/100 pacientes/ano. Os sangramentos apresentaram associação com possuir mais que três interações medicamentosas com a varfarina (p=0,048) e com uso de medicamentos por automedicação (p=0,030). Já para o TTR houve associação com a idade inferior a 65 anos (p=0,032). E 67 usuários estavam suscetíveis a interações medicamentosasas com varfarina, com predomínio das moderadas, sendo a média de interações com este medicamento de 2,91±1,52. A maioria das interações agiam sobre o efeito anticoagulante da varfarina, aumentando a probabilidade de sangramento. Entre as interações que os usuários apresentavam, no momento do sangramento, as mais frequentes foram com: omeprazol, sinvastatina e paracetamol. A maioria dos entrevistados apresentou consumo baixo de vitamina K. Verificou-se que sangramentos e tromboembolismos venosos foram mais frequentes nos pacientes em início de tratamento. E todos os pacientes que foram a óbito durante o acompanhamento (5) eram pacientes com mais de um ano de uso de varfarina. Para a resolução de eventos adversos na maioria dos casos o paciente realizou cuidado domiciliar (53,4%), seguido por busca pela Unidades Básicas de Saúde, 7 pacientes buscaram o serviço de emergência e 5 realizaram internação hospitalar. Observou-se que aproximadamente metade dos pacientes não mostrou seus exames de INR (Razão Normalizada Internacional) ao médico. E na falta de varfarina na rede pública de saúde do município, que ocorreu entre os meses 13 e 16, entre 24,9 a 43,5%, deixaram de usar o medicamento. Os resultados do polimorfismo demonstram que 47 (71,2%) não apresentam polimorfismo ao genótipo CYP2C9, e 24 (36,4%) ao genótipo VKORC1. Avaliando os dois genótipos associados, verifica-se que 17 (25,8%) não apresentam polimorfismo a nenhum destes. Não foi observada associação estatística do polimorfismo com sexo e raça. Observou-se diferença significativa entre a dose utilizada para os diferentes polimorfismos (p=0,013). Da mesma forma, para o VKORC1, houve diferença significativa entre a dose e o genótipo (p=0,018). Conclusão: Estes resultados demonstram a necessidade de uma maior assistência a estes pacientes, buscando melhores resultados clínicos, com menos eventos adversos. / Introduction: Warfarin is an oral anticoagulant (OAC) most used in primary health care. With narrow therapeutic window, shows great variability in drug response, and greater susceptibility to adverse events such as bleeding and venous thromboembolism. Among the factors that influence the amount of variability highlights the interactions with both drugs, as with diet and genetic polymorphism. Objectives: To estimate the incidence of adverse events related to warfarin use and describe the user journey through the public health system to the problems. Methods: This is a prospective cohort study conducted over a period of 18 months with users of the public health service in the use of warfarin, the city of Ijuí/RS. The data were collected monthly interviews in homes and complemented with medical information obtained in primary and tertiary care. Drug interactions were checked in databases and eating habits as validated methodology. The statistics used to associate bleeding and Time in Therapeutic Range (TTR) and the risk factors was Poison test. The project was approved by the Research Ethics Committee of UFRGS, with opinion number 336259/2013. Results: We interviewed and followed 69 patients, 64 completed the follow-up and 5 died during the study, 55.1% were female, mean age 64.3 ± 13.7 years. The mean duration of warfarin use was 5.5 years, the average weekly dose was 30.69 ± 15,19mg and the main reason for warfarin use was valvular prosthesis (39.7%). The average per user used medications was 9.6 ± 4.5. As for events, the bleeding had incidence of 37.7 / 100 patients / year, thromboembolism of 4.8 / 100 patients / year and deaths of 4.8 / 100 patients / year. Bleeds were associated with having more than three drug interactions with warfarin (p = 0.048) and use of self-medication by drugs (p = 0.030). As for the TTR was no association with age less than 65 years (p = 0.032). And 67 users were susceptible to medicamentosasas interactions with warfarin, with a predominance of moderate, with an average of interactions with this drug of 2.91 ± 1.52. Most interactions acting on the anticoagulant effect of warfarin, increasing the probability of bleeding. Among the interactions that users had, at the time of bleeding, the most common were with: omeprazole, simvastatin and acetaminophen. Most respondents showed low consumption of vitamin K. It was found that bleeding and venous thromboembolism were more frequent in patients starting treatment. And all patients who died during follow-up (5) were patients with more than one year of warfarin use. For adverse event resolution in most cases the patient underwent home care (53.4%), followed by search for the Basic Health Units, 7 patients sought emergency services and 5 held hospitalization. It was observed that approximately half of the patients showed their INR test (International Normalized Ratio) to the doctor. And in the absence of warfarin in public municipal health, which occurred between the months 13:16, from 24.9 to 43.5% stopped using the drug. The polymorphism results demonstrate that 47 (71.2%) did not have the polymorphism CYP2C9 genotype, and 24 (36.4%) the VKORC1 genotype. Evaluating the two genotypes associated, it is found that 17 (25.8%) did not show any polymorphism thereof. There was no statistical association of the polymorphism with gender and race. A significant difference between the dose for different polymorphisms (p = 0.013). Likewise, for the VKORC1, a significant difference between the dose and genotype (p = 0.018). Conclusion: These results demonstrate the need for further assistance to these patients, looking for better clinical outcomes, with fewer adverse events.