Ambient air pollution and emergency department visits and hospitalisation for cardiac arrest: a population-based case-crossover study in Reykjavik, Iceland.

OBJECTIVES: To assess the association between traffic-related ambient air pollution and emergency hospital visits for cardiac arrest. DESIGN: Case-crossover design was used with a lag time to 4 days. SETTING: The Reykjavik capital area and the study population was the inhabitants 18 years and older identified by encrypted personal identification numbers and zip codes. PARTICIPANTS AND EXPOSURE: Cases were those with emergency visits to Landspitali University Hospital during the period 2006-2017 and who were given the primary discharge diagnosis of cardiac arrest according to the International Classification of Diseases 10th edition (ICD-10) code I46. The pollutants were nitrogen dioxide (NO2), particulate matter with aerodynamic diameter less than 10 µm (PM10), particulate matter with aerodynamic diameter less than 2.5 µm (PM2.5) and sulfur dioxide (SO2) with adjustment for hydrogen sulfide (H2S), temperature and relative humidity. MAIN OUTCOME MEASURE: OR and 95% CIs per 10 µg/m3 increase in concentration of pollutants. RESULTS: The 24-hour mean NO2 was 20.7 µg/m3, mean PM10 was 20.5 µg/m3, mean PM2.5 was 12.5 µg/m3 and mean SO2 was 2.5 µg/m3. PM10 level was positively associated with the number of emergency hospital visits (n=453) for cardiac arrest. Each 10 µg/m3 increase in PM10 was associated with increased risk of cardiac arrest (ICD-10: I46), OR 1.096 (95% CI 1.033 to 1.162) on lag 2, OR 1.118 (95% CI 1.031 to 1.212) on lag 0-2, OR 1.150 (95% CI 1.050 to 1.261) on lag 0-3 and OR 1.168 (95% CI 1.054 to 1.295) on lag 0-4. Significant associations were shown between exposure to PM10 on lag 2 and lag 0-2 and increased risk of cardiac arrest in the age, gender and season strata. CONCLUSIONS: A new endpoint was used for the first time in this study: cardiac arrest (ICD-10 code: I46) according to hospital discharge registry. Short-term increase in PM10 concentrations was associated with cardiac arrest. Future ecological studies of this type and their related discussions should perhaps concentrate more on precisely defined endpoints.

Accidental poisoning, intentional self-harm and event of undetermined intent mortality over 20 years in Iceland: a population-based cohort study.

OBJECTIVES: The aim was to study mortality due to suicide, accidental poisoning, event of undetermined intent and drug-related deaths through 20 years in Iceland. DESIGN: A population-based register study. PARTICIPANTS: Individuals who died due to road traffic injury, suicide, accidental poisoning, event of undetermined intent and drug-related deaths in the population of Iceland during the years 1996-2015. Annual age-standardised rates were calculated, and the trend analysed by Pearson correlation and joinpoint regression. SETTING: The population of Iceland framed the study material, and the data were obtained from nationwide registries for information on number of deaths and age-specific mean population in each year by gender. RESULTS: The crude overall suicide rate during the last 10 years was 12.2 per 100 000 persons per year (95% CI 7.4 to 18.1), while the crude overall rate due to road traffic injuries was 4.6 per 100 000 persons per year (95% CI 2.0 to 8.3). Among men, suicide rates decreased, however not significantly (r(19)=-0.22, p=0.36), and for overdose by narcotics the rates increased significantly (r(19)=0.72, p<0.001) during the study period. Among women, the suicide rates increased, however not significantly (r(19)=0.35, p=0.13), for accidental poisoning, suicide and event of undetermined intent combined the rates increased significantly (r(19)=0.60, p=0.006); and the rates for overdose by sedative and overdose by narcotics both increased significantly r(19)=0.49, p=0.03, and r(19)=0.67, p=0.001, respectively. CONCLUSION: The suicide rates have not changed during 1996 to 2015; however, the rates for the combined accidental poisoning, suicide and event of undetermined intent increased significantly for women. The rise of the overdose rates for sedative among women and for narcotics among both genders are consistent with reports elsewhere.

Number of visits to the emergency department and risk of suicide: a population-based case-control study.

BACKGROUND: The aim was to study whether number of visits to emergency department (ED) is associated with suicide, taking into consideration known risk factors. METHODS: This is a population-based case-control study nested in a cohort. Computerized database on attendees to ED (during 2002-2008) was record linked to nation-wide death registry to identify 152 cases, and randomly selected 1520 controls. The study was confined to patients attending the ED, who were subsequently discharged, and not admitted to hospital ward. Odds ratio (OR) and 95% confidence intervals (CI) of suicide risk according to number of visits (logistic regression) adjusted for age, gender, mental and behavioral disorders, non-causative diagnosis, and drug poisonings. RESULTS: Suicide cases had on average attended the ED four times, while controls attended twice. The OR for attendance due to mental and behavioral disorders was 3.08 (95% CI 1.61-5.88), 1.60 (95% CI 1.06-2.43) for non-causative diagnosis, and 5.08 (95% CI 1.69-15.25) for poisoning. The ORs increased gradually with increasing number of visits. Adjusted for age, gender, and the above mentioned diagnoses, the OR for three attendances was 2.17, for five attendances 2.60, for seven attendances 5.97, and for nine attendances 12.18 compared with those who had one visit. CONCLUSIONS: Number of visits to the ED is an independent risk factor for suicide adjusted for other known and important risk factors. The prevalence of four or more visits was 40% among cases compared with 10% among controls. This new risk factor may open new venues for suicide prevention.

Survival of patients with alcohol use disorders discharged from an emergency department: a population-based cohort study.

OBJECTIVES: The aim was to study the cause-specific mortality of users of the emergency department (ED) who received a diagnosis of alcohol use disorder (AUD) in comparison with mortality of other users of the department. DESIGN: A population-based prospective cohort study. PARTICIPANTS: All patients aged 18 years and above who were subsequently discharged home from the ED during the years 2002-2008. A total of 107,237 patients were followed by record linkage to a nationwide cause-of-death registry: 1210 patients with AUD as the main discharge diagnosis and 106,027 patients in the comparison group. HR and 95% CIs were calculated. SETTING: ED at Landspitali-the National University Hospital of Iceland, Reykjavik, Iceland. The hospital offers tertiary care and is the number one trauma centre and community hospital for the greater Reykjavik area. According to the population registry, 78% of the inhabitants of the area attended the ED during the study period. RESULTS: 72 patients died in the AUD group and 4807 in the comparison group. The adjusted HR for all causes of death was 1.91 (95% CI 1.51 to 2.42). The HR for AUDs was 47.68 (95% CI 11.56 to 196.59) while for alcohol liver disease the HR was 19.06 (95% CI 6.07 to 59.87). The HR was also elevated for diseases of the circulatory system: HR 2.52 (95% CI 1.73 to 3.68); accidental poisoning: HR=13.64, (95% CI 3.98 to 46.73); suicide: HR=2.72 (95% CI 1.08 to 6.83); and event of undetermined intent: HR=10.89 (95% CI 4.53 to 26.16). CONCLUSIONS: AUD as the discharge diagnosis at the ED, among patients who were not admitted to a hospital ward but discharged home, predicts increased mortality. As the results conclusively show the vulnerability of these patients, one can question whether their needs are adequately met at the ED.

Risk of repeat visits, hospitalisation and death after uncompleted and completed visits to the emergency department: a prospective observation study.

OBJECTIVES: The needs of patients with uncompleted visits to the emergency department (ED) are uncertain. The aim was to evaluate ED patients who leave against medical advice (AMA) and who leave without being seen (WBS) regarding repeat ED visits, hospitalisation and mortality within 30 days. METHODS: The National University Hospital operates the only ED for adults in the capital area of Reykjavik. The source of data was the electronic records for patients 18 years or older, who left AMA, who left WBS, who had the ICD-10 code Z53.2, or who completed their visits. ED visits, hospital admissions and the death registry are filed with the personal identification number, which enabled recognition of the index visit, and the outcomes, rates of return visits, hospitalisation and death. RESULTS: Of 107 119 patients, 77 left AMA, 4471 left WBS and 423 had code Z53.2. The HR for returning to the ED within 30 days was 4.79 for AMA patients, 4.84 for WBS patients and 3.67 for Z53.2 patients. The HR for hospitalisation within 30 days was 6.90 for AMA patients, 1.09 for WBS patients and 1.07 for Z53.2 patients. The HR for death within 30 days was 10.97 for AMA patients, 0.84 for WBS and no deaths occurred among Z53.2 patients. DISCUSSION: During 30 days follow-up, AMA and WBS patients had an increased rate of repeat ED visits compared with those patients who completed their ED visits. AMA patients also had an increased rate of hospitalisations.