Unravelling the role of the mandatory use of face covering masks for the control of SARS-CoV-2 in schools: a quasi-experimental study nested in a population-based cohort in Catalonia (Spain).

OBJECTIVE: To assess the effectiveness of mandatory use of face covering masks (FCMs) in schools during the first term of the 2021-2022 academic year. DESIGN: A retrospective population-based study. SETTING: Schools in Catalonia (Spain). POPULATION: 599 314 children aged 3-11 years attending preschool (3-5 years, without FCM mandate) and primary education (6-11 years, with FCM mandate). STUDY PERIOD: From 13 September to 22 December 2021 (before Omicron variant). INTERVENTIONS: A quasi-experimental comparison between children in the last grade of preschool (5 years old), as a control group, and children in year 1 of primary education (6 years old), as an interventional group. MAIN OUTCOME MEASURES: Incidence of SARS-CoV-2, secondary attack rates (SARs) and effective reproductive number (R*). RESULTS: SARS-CoV-2 incidence was significantly lower in preschool than in primary education, and an increasing trend with age was observed. Six-year-old children showed higher incidence than 5 year olds (3.54% vs 3.1%; OR 1.15 (95% CI 1.08 to 1.22)) and slightly lower but not statistically significant SAR (4.36% vs 4.59%; incidence risk ratio 0.96 (95% CI 0.82 to 1.11)) and R* (0.9 vs 0.93; OR 0.96 (95% CI 0.87 to 1.09)). Results remained consistent using a regression discontinuity design and linear regression extrapolation approaches. CONCLUSIONS: We found no significant differences in SARS-CoV-2 transmission due to FCM mandates in Catalonian schools. Instead, age was the most important factor in explaining the transmission risk for children attending school.

Excess cases of influenza and the coronavirus epidemic in Catalonia: a time-series analysis of primary-care electronic medical records covering over 6 million people.

OBJECTIVES: There is uncertainty about when the first cases of COVID-19 appeared in Spain. We aimed to determine whether influenza diagnoses masked early COVID-19 cases and estimate numbers of undetected COVID-19 cases. DESIGN: Time-series study of influenza and COVID-19 cases, 2010-2020. SETTING: Primary care, Catalonia, Spain. PARTICIPANTS: People registered in primary-care practices, covering >6 million people and >85% of the population. MAIN OUTCOME MEASURES: Weekly new cases of influenza and COVID-19 clinically diagnosed in primary care. ANALYSES: Daily counts of both cases were computed using the total cases recorded over the previous 7 days to avoid weekly effects. Epidemic curves were characterised for the 2010-2011 to 2019-2020 influenza seasons. Influenza seasons with a similar epidemic curve and peak case number as the 2019-2020 season were used to model expected case numbers with Auto Regressive Integrated Moving Average models, overall and stratified by age. Daily excess influenza cases were defined as the number of observed minus expected cases. RESULTS: Four influenza season curves (2011-2012, 2012-2013, 2013-2014 and 2016-2017) were used to estimate the number of expected cases of influenza in 2019-2020. Between 4 February 2020 and 20 March 2020, 8017 (95% CI: 1841 to 14 718) excess influenza cases were identified. This excess was highest in the 15-64 age group. CONCLUSIONS: COVID-19 cases may have been present in the Catalan population when the first imported case was reported on 25 February 2020. COVID-19 carriers may have been misclassified as influenza diagnoses in primary care, boosting community transmission before public health measures were taken. The use of clinical codes could misrepresent the true occurrence of the disease. Serological or PCR testing should be used to confirm these findings. In future, this surveillance of excess influenza could help detect new outbreaks of COVID-19 or other influenza-like pathogens, to initiate early public health responses.

Rheumatoid factor testing in Spanish primary care: A population-based cohort study including 4.8 million subjects and almost half a million measurements.

OBJECTIVE: Rheumatoid factor (RF) testing is used in primary care in the diagnosis of rheumatoid arthritis (RA); however a positive RF may occur without RA. Incorrect use of RF testing may lead to increased costs and delayed diagnoses. The aim was to assess the performance of RF as a test for RA and to estimate the costs associated with its use in a primary care setting. MATERIAL AND METHODS: A retrospective cohort study using the Information System for the Development of Research in Primary Care database (contains primary care records and laboratory results of >80% of the Catalonian population, Spain). Participants were patients ≥18 years with ≥1 RF test performed between 01/01/2006 and 31/12/2011, without a pre-existing diagnosis of RA. Outcome measures were an incident diagnosis of RA within 1 year of testing, and the cost of testing per case of RA. RESULTS: 495,434/4,796,498 (10.3%) patients were tested at least once. 107,362 (21.7%) of those tested were sero-positive of which 2768 (2.6%) were diagnosed with RA within 1 year as were 1141/388,072 (0.3%) sero-negative participants. The sensitivity of RF was 70.8% (95% CI 69.4-72.2), specificity 78.7% (78.6-78.8), and positive and negative predictive values 2.6% (2.5-2.7) and 99.7% (99.6-99.7) respectively. Approximately €3,963,472 was spent, with a cost of €1432 per true positive case. CONCLUSIONS: Although 10% of patients were tested for RF, most did not have RA. Limiting testing to patients with a higher pre-test probability would significantly reduce the cost of testing.

Socioeconomic status and its association with the risk of developing hip fractures: a region-wide ecological study.

PURPOSE: To determine the association between socioeconomic deprivation (SES) and hip fracture risk. METHODS: Retrospective cohort study using a population-based database (primary care records) of over 5 million people. Eligibility: all living subjects registered during the period 2009-2012 and resident in an urban area. MEASURES: a validated SES composite index (proportion of unemployed, temporary workers, manual workers, low educational attainment and low educational attainment among youngsters) estimated for each area based on census data. OUTCOME: incident hip fracture rates as coded in medical records using ICD-10 codes. STATISTICS: zero-inflated Poisson models fitted to study the association between SES quintiles and hip fracture risk, adjusted for age, sex, obesity, smoking and alcohol consumption. RESULTS: Compared to the most deprived, wealthy areas had a higher hip fracture incidence (age- and sex-adjusted incidence 38.57 (37.14-40.00) compared to 34.33 (32.90-35.76) per 10,000 person-years). Similarly, most deprived areas had a crude and age- and sex-adjusted lower risk of hip fracture, RR of 0.71 (0.65-0.78) and RR of 0.90 (0.85-0.95), respectively, compared to wealthiest areas. The association was attenuated and no longer significant after adjustment for obesity: RR 0.96 (0.90-1.01). Further adjustment for smoking and high alcohol consumption did not make a difference. CONCLUSION: Wealthiest areas have an almost 30% increased risk of hip fracture compared to the most deprived. Differences in age-sex composition and a higher prevalence of obesity in deprived areas could explain this higher risk.

Rheumatoid factor testing in Spanish primary care: A population-based cohort study including 4.8 million subjects and almost half a million measurements / Uso del factor reumatoide en atención primaria en España: estudio de cohortes poblacionales incluyendo 4.8 millones de participantes y casi medio millón de mediciones

OBJECTIVE: Rheumatoid factor (RF) testing is used in primary care in the diagnosis of rheumatoid arthritis (RA); however a positive RF may occur without RA. Incorrect use of RF testing may lead to increased costs and delayed diagnoses. The aim was to assess the performance of RF as a test for RA and to estimate the costs associated with its use in a primary care setting. MATERIAL AND METHODS: A retrospective cohort study using the Information System for the Development of Research in Primary Care database (contains primary care records and laboratory results of >80% of the Catalonian population, Spain). Participants were patients ≥18 years with ≥1 RF test performed between 01/01/2006 and 31/12/2011, without a pre-existing diagnosis of RA. Outcome measures were an incident diagnosis of RA within 1 year of testing, and the cost of testing per case of RA. RESULTS: 495,434/4,796,498 (10.3%) patients were tested at least once.107,362 (21.7%) of those tested were sero-positive of which 2768 (2.6%) were diagnosed with RA within 1 year as were 1141/388,072 (0.3%) sero-negative participants. The sensitivity of RF was 70.8% (95% CI 69.4-72.2), specificity 78.7% (78.6-78.8), and positive and negative predictive values 2.6% (2.5-2.7) and 99.7% (99.6-99.7) respectively. Approximately €3,963,472 was spent, with a cost of €1432 per true positive case. CONCLUSIONS: Although 10% of patients were tested for RF, most did not have RA. Limiting testing to patients with a higher pre-test probability would significantly reduce the cost of testing

OBJETIVOS: El factor reumatoide (FR) se usa en atención primaria para el diagnóstico de la artritis reumatoide (AR); sin embargo, un FR positivo puede observarse en sujetos sin AR, y su uso inapropiado puede conllevar costes y retraso diagnóstico. En este contexto, estudiamos la utilidad y costes del FR como test diagnóstico de la AR en atención primaria. MÉTODOS: Estudio de cohortes retrospectivas basadas en datos de historia clínica informatizada de >80% de la población de Cataluña (SIDIAP). Se incluyeron sujetos de edad ≥18 años y con ≥1 medida de FR entre el 1/1/2006 y el 31/12/2011, sin diagnóstico previo de AR. El diagnóstico incidente de AR durante el año posterior a la medida de FR, y el coste por caso de AR fueron las medidas de interés. RESULTADOS: 495.434/4.796.498 (10,3%) pacientes tuvieron al menos una medida de FR 107.362 (21,7%) de estos fueron sero-positivos, de los cuales solo 2.768 (2,6%) fueron diagnosticados de AR en el año siguiente, comparado a 1.141/388.072 (0,3%) diagnósticos en sero-negativos. La sensibilidad del FR fue del 70,8% (IC 95%: 69,4 a 72,2%), especificidad 78,7% (78,6 a 78,8%), y valor predictivo positivo y negativo 2,6% (2,5 a 2,7%) y 99,7% (99,6 a 99,7%), respectivamente. El coste total estimado fue de 3.963,472€, alrededor de 1.432€ por caso de AR diagnosticado. CONCLUSIONES: Aunque el 10% de participantes (casi medio millón de personas) fueron sujetos de medición/es de FR, la mayoría no desarrollaron AR. El uso de FR en pacientes con mayor probabilidad pre-test reduciría de forma significativa su coste

The association between fracture site and obesity in men: a population-based cohort study.

A site-dependent association between obesity and fracture has been reported in postmenopausal women. In this study we investigated the relationship between body mass index (BMI) and fracture at different skeletal sites in older men (≥65 years). We carried out a population-based cohort study using data from the Sistema d'Informació per al Desenvolupament de l'Investigació en Atenció Primària (SIDIAP(Q) ) database. SIDIAP(Q) contains the primary care and hospital admission computerized medical records of >1300 general practitioners (GPs) in Catalonia (Northeast Spain), with information on a representative 30% of the population (>2 million people). In 2007, 186,171 men ≥65 years were eligible, of whom 139,419 (74.9%) had an available BMI measurement. For this analysis men were categorized as underweight/normal (BMI < 25 kg/m(2) , n = 26,298), overweight (25 ≤ BMI < 30 kg/m(2) , n = 70,851), and obese (BMI ≥ 30 kg/m(2) , n = 42,270). Incident fractures in the period 2007 to 2009 were ascertained using International Classification of Diseases, 10th edition (ICD-10) codes. A statistically significant reduction in clinical spine and hip fractures was observed in obese (relative risk [RR], 0.65; 95% confidence interval [CI], 0.53-0.80 and RR, 0.63; 95% CI, 0.54-0.74, respectively), and overweight men (RR, 0.77; 95% CI, 0.64-0.92 and RR, 0.63; 95% CI 0.55-0.72, respectively) when compared with underweight/normal men. Additionally, obese men had significantly fewer wrist/forearm (RR, 0.77; 95% CI, 0.61-0.97) and pelvic (RR, 0.44; 95% CI, 0.28-0.70) fractures than underweight/normal men. Conversely, multiple rib fractures were more frequent in overweight (RR, 3.42; 95% CI, 1.03-11.37) and obese (RR, 3.96; 95% CI, 1.16-13.52) men. In this population-based cohort of older men, obesity was associated with a reduced risk of clinical spine, hip, pelvis, and wrist/forearm fracture and increased risk of multiple rib fractures when compared to normal or underweight men. Further work is needed to identify the mechanisms underlying these associations.

The association between fracture and obesity is site-dependent: a population-based study in postmenopausal women.

The association between obesity and fracture is controversial. We investigated the relationship between body mass index (BMI) and fracture at different skeletal sites in women aged ≥50 years using data from the Sistema d' Informació per al Desenvolupament de la Investigació en Atenció Primària (SIDIAP) database. SIDIAP contains the computerized medical records of >3400 general practitioners in Catalonia (northeastern Spain), with information on a representative 80% of the population (>5 million people). In 2009, 1,039,878 women aged ≥50 years were eligible, of whom 832,775 (80.1%) had a BMI measurement. These were categorized into underweight/normal (302,414 women), overweight (266,798), and obese (263,563). Fractures were ascertained using the International Classification of Diseases, 10th revision (ICD-10) codes. Multivariate Poisson regression models were fitted to adjust for age, smoking, high alcohol intake, type 2 diabetes, and oral corticosteroid use. Hip fractures were significantly less common in overweight and obese women than in normal/underweight women (rate ratio [RR] 0.77 [95% confidence interval (CI) 0.68 to 0.88], RR 0.63 [95% CI 0.64 to 0.79], p < 0.001, respectively). Pelvis fracture rates were lower in the overweight (RR 0.78 [95% CI 0.63 to 0.96], p = 0.017) and obese (RR 0.58 [95% CI 0.47 to 0.73], p < 0.001) groups. Conversely, obese women were at significantly higher risk of proximal humerus fracture than the normal/underweight group (RR 1.28 [95% CI 1.04 to 1.58], p = 0.018). Clinical spine, wrist, tibial, and multiple rib fracture rates were not significantly different between groups. An age-related increase in incidence was seen for all BMI groups at all fracture sites; obese women with hip, clinical spine, and pelvis fracture were significantly younger at the time of fracture than normal/underweight women, whereas those with wrist fracture were significantly older. The association between obesity and fracture in postmenopausal women is site-dependent, obesity being protective against hip and pelvis fractures but associated with an almost 30% increase in risk for proximal humerus fractures when compared with normal/underweight women. The reasons for these site-specific variations are unknown but may be related to different patterns of falls and attenuation of their impact by adipose tissue.

La enfermedad de Alzheimer y otras demencias en el Sistema de Información para el Desarrollo de la Investigación en Atención Primaria (SIDIAP) / Alzheimer's disease and other dementias in the InformationSystem for Primary Care Research Development (SIDIAP)

La informatización de la historia clínica en el ámbito de la Atención Primaria proporciona un gran potencial para la investigación, particularmente en estudios de prevalencia e incidencia, en estudios de evaluación de servicios de salud y en estudios de farmacoepidemiología. El Institut Català de la Salut y el IDIAP Jordi Gol crearon SIDIAP en el año 2010. Esta base de datos contiene la información clínica registrada por profesionales de atención primaria de la salud (médicos y enfermeras) y personal administrativo de los registros médicos electrónicos, incluyendo las características sociodemográficas, la morbilidad (Clasificación Inter - nacional de Enfermedades, CIE-10), variables clínicas y de estilos de vida, pruebas de laboratorio y tratamientos (prescripciones médicas, medicamentos dispensados en la farmacia), y también información de las altas hospitalarias. La base de datos contiene esta información de cerca de cinco millones de personas, lo que representa aproximadamente el 80 % de la población total mayor de 15 años de edad de Cataluña. Las bases de datos de atención primaria como SIDIAP presentan unas claras ventajas en relación con otras fuentes de información: contienen grandes muestras, permiten seguimientos de larga duración, tienen bajo coste, permiten relación con múltiples fuentes de información, no interfieren en la práctica clínica, y aportan representatividad de la práctica real. La demencia de Alzheimer (DA) es un claro ejemplo de patología para la que la información adicional que pueden proporcionar estudios realizados en la base de datos SIDIAP puede ser de gran utilidad. SIDIAP permite diseñar estudios transversales para el análisis de patrones de tratamientos o comorbilidades asociadas a las demencias; estudios de cohortes con largos períodos de seguimiento o estudios de caso y control para evaluar factores de riesgo asociados a la aparición de las distintas demencias y estudios de efectividad de los tratamientos y las intervenciones preventivas (AU)

Computerized databases of primary care clinical records are widely used for epidemiological research, particularly in studies of disease prevalence and incidence, studies of health services and in pharmacoepidemiological research. The Information System for the Development of Research in Primary Care (SIDIAP) was created in 2010 by the Catalan Institute of Health (ICS) and the Jordi Gol Primary Care Research Institute (IDIAP Jordi Gol). SIDIAP comprises clinical information recorded by primary care health professionals (GPs and nurses) and administrative staff in electronic medical records, including sociodemographic characteristics, morbidity (International Classification of Diseases, ICD-10), clinical and lifestyle variables, laboratory tests and treatments (drug prescriptions, drugs purchased at the community pharmacy) and also hospital discharge information. The database contains this information for almost five million people, representing approximately 80% of the total population aged over 15 years old in Catalonia (north-east Spain). The fact that these databases can provide large sample sizes at a comparatively low cost and that they permit long follow-up periods without directly requiring the participation of the subjects, whilst minimizing biases such as the Healthy Worker and the Hawthorne effects, has made them especially interesting for public health research. Alzheimer's dementia is a clear example of pathology in which the information provided by SIDIAP can be very useful for research purposes. SIDIAP allows cross-sectional studies for the analysis of treatment patterns or co-morbidities associated with dementia; cohort studies with long follow- up periods or case-control study to evaluate risk factors associated with the onset of various dementias and also permit studies of effectiveness of treatments and preventive interventions (AU)

Base de datos SIDIAP: la historia clínica informatizada de Atención Primaria como fuente de información para la investigación epidemiológica / SIDIAP database: electronic clinical records in Primary Care as a source of information for epidemiologic research

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