Risk of Diabetic Retinopathy According to Subtype of Type 2 Diabetes

Type 2 diabetes is a heterogeneous disease that can be subdivided on the basis of β-cell function and insulin sensitivity. We investigated the presence, incidence, and progression of diabetic retinopathy (DR) according to subtypes of type 2 diabetes. In a national cohort, we identified three subtypes of type 2 diabetes: classical, hyperinsulinemic, and insulinopenic type 2 diabetes, based on HOMA2 measurements. From the Danish Registry of Diabetic Retinopathy we extracted information on level of DR. We used several national health registries to link information on comorbidity, medications, and laboratory tests. We found individuals with hyperinsulinemic type 2 diabetes were less likely to have DR at entry date compared with those with classical type 2 diabetes, whereas individuals with insulinopenic type 2 diabetes were more likely to have DR. In multivariable Cox regression analysis, individuals with hyperinsulinemic type 2 diabetes had a decreased risk of both incidence and progression of DR compared to those with classical type 2 diabetes. We did not find any clear difference in risk of incident or progression of DR in individuals with insulinopenic compared to classical type 2 diabetes. These findings indicate that subcategorization of type 2 diabetes is important in evaluating the risk of DR.

ARTICLE HIGHLIGHTS

Presence and development of diabetic retinopathy in 16 999 patients with type 1 diabetes in the Danish Registry of Diabetic Retinopathy

PURPOSE

To evaluate the five-year incidence of diabetic retinopathy (DR) and associated risk markers in patients with type 1 diabetes in the national Danish DR-screening programme.

METHODS

Based on national data, we included all 16 999 patients with type 1 diabetes in the Danish Registry of Diabetic Retinopathy, who attended the national screening programme in the period 2013-2018. According to the worse eye at first screening, DR was classified (levels 0-4) and linked with various national health registries to retrieve information on diabetes duration, systemic comorbidity, and medication.

RESULTS

At first screening, median age and duration of diabetes were 45.0 and 16.7 years, and 57.5% were males. The prevalence and five-year incidences for DR and progression to proliferative DR (PDR) were 44.2%, 8.9% and 2.0%, respectively. In multivariable Cox models, the incidence endpoints were associated with duration of diabetes (hazard ratio [HR] 1.76, 95% confidence interval [CI] 1.63-1.89, and HR 2.04, 95% CI 1.73-2.40 per 10 years), moderately low Charlson Comorbidity Index score (HR 1.27, 95% CI 1.10-1.47, and HR 2.80, 95% CI 2.23-3.51), and use of blood pressure lowering medication (HR 1.20, 95% CI 1.05-1.36, and HR 1.98, 95% CI 1.53-2.57).

CONCLUSION

In a study of all patients with type 1 diabetes from the Danish DR-screening programme, we identified duration of diabetes, systemic disease and use of anti-hypertensive treatment as consistent risk markers for incident and progressive DR.

VEGF Inhibition Associates With Decreased Risk of Mortality in Patients With Neovascular Age-related Macular Degeneration

Purpose

Controversy exists regarding the systemic safety of intravitreal VEGF inhibitors in the treatment of neovascular age-related macular degeneration (nAMD). We aimed to investigate the potential impact of VEGF inhibitor treatment on the risk of all-cause mortality and cardiovascular disease (CVD) among patients with nAMD.

Design

A nationwide register-based cohort study with 16 years follow-up.

Participants

Patients with nAMD exposed with VEGF inhibitors (n = 37 733) and unexposed individuals without nAMD (n = 1 897 073) aged ≥ 65 years residing in Denmark between January 1, 2007, and December 31, 2022.

Methods

Cox proportional hazards analysis was conducted to assess the effect of intravitreal VEGF inhibitor treatment on all-cause mortality and incident CVD.

Main Outcome Measures

In a predefined analysis plan we defined primary outcomes as hazard ratios (HRs) of all-cause mortality and a composite CVD endpoint in patients with nAMD treated with VEGF inhibitors compared with individuals without nAMD. The secondary outcomes encompassed analyses that explored the impact of the number of doses and the association between exposure and outcome over a specific time period.

Results

Overall, 63.7% of patients with nAMD were women with an average age of 69.9 years (interquartile range 65.0-76.0 years). Patients exposed to VEGF inhibitors demonstrated a reduced risk of all-cause mortality compared with individuals without nAMD (HR, 0.79; 95% confidence interval [CI], 0.78-0.81), and an increased risk of composite CVD (HR, 1.04; 95% CI, 1.01-1.07). The decreased risk of all-cause mortality persisted, but there was no significant association between VEGF inhibitor treatment and CVD when patients with nAMD were grouped by the number of doses or considered exposed within 60 days postinjection.

Conclusions

Our study revealed a decreased risk of all-cause mortality and a 4% increased risk of CVD among patients with nAMD exposed with VEGF inhibitors. The decreased risk of mortality is unlikely to be directly pathophysiologically related to VEGF inhibitor treatment. Instead, we speculate that patients undergoing VEGF inhibitor treatment are, on average, individuals in good health with adequate personal resources. Therefore, they also have a higher likelihood of overall survival. These findings strongly support the safety of VEGF inhibitor treatment in terms of all-cause mortality and CVD among patients with nAMD.

Financial Disclosures

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Structural and Metabolic Retinal Changes Associated With Mild Cognitive Impairment in Type 2 Diabetes

Type 2 diabetes is associated with cognitive impairment and a twofold increased risk of dementia compared with age-matched individuals without diabetes. Given that the eye and the brain share similar embryologic origin and anatomical features, the retina offers a unique window to the brain. In this study, we wanted to determine whether there was a difference in retinal imaging-based neuronal and vascular markers in individuals with type 2 diabetes with or without mild cognitive impairment (MCI). We included 134 persons with type 2 diabetes. Based on neuropsychological tests, the prevalence of MCI was 28%. We performed seven-field color fundus photos, optical coherence tomography (OCT), OCT-angiography (OCT-A), and retinal oximetry to analyze retinal markers. In a multivariable cluster analysis, persons with MCI had a significantly thinner macular retinal nerve fiber layer and macular ganglion cell layer, and less venular oxygen saturation in the nasal quadrant compared with those without MCI. There were no differences in retinal vessel density, fractal dimension, width, tortuosity, or OCT-A markers. People with type 2 diabetes and MCI demonstrate alterations in retinal structure and metabolism, suggesting noninvasive retinal markers may be useful to detect people with type 2 diabetes at risk for cognitive dysfunction.

ARTICLE HIGHLIGHTS

Type 2 diabetes is associated with mild cognitive impairment (MCI). Therefore, retinal and cerebral neurodegeneration may run in parallel. To assess whether there was a difference in retinal structure, vessel, and metabolic parameters in individuals with MCI. We found those with MCI had a thinner macular retinal nerve fiber layer, macular ganglion cell layer, and less venular oxygen saturation. We suggest noninvasive retinal markers may be useful to detect those at risk of cognitive dysfunction.

Patient perspectives and barriers in the treatment of neovascular age-related macular degeneration in Denmark: a qualitative study

OBJECTIVES

This qualitative study aims to identify patient-reported barriers to treatment for neovascular age-related macular degeneration (nAMD) and investigate their impact on quality of life.

DESIGN

Using a qualitative explorative design.

SETTING

Semi-structured individual or dyadic interviews were conducted with patients and their relatives.

PARTICIPANTS

Twenty-one patients completed the interview, with four of them having a relative present.

INTERVENTIONS

Gadamer's hermeneutics guided the epistemological approach, and maximum variation sampling was employed to capture diverse patient experiences. An advisory board consisting of patients, relatives and ophthalmologists ensured the relevance of the study. Thematic analysis was conducted using NVivo software.

PRIMARY AND SECONDARY OUTCOME MEASURES

To investigate patient-reported barriers to the recommended treatment for nAMD and impact on quality of life.

RESULTS

The study included 21 patients with nAMD, with a median age of 79 years. Five themes emerged: (1) good compliance with intravitreal treatment, (2) the dual role of relatives, (3) treatment commute, (4) hospital barriers, (5) preventive health literacy.

CONCLUSION

This study highlights the resilience and adherence of patients with nAMD in Denmark to their treatment despite various barriers. While the therapy may have negative effects on their well-being, patients do not opt out of treatment. These findings underscore the importance of personalised treatment plans that provide, for example, convenient access to care and clear future agreements at the hospital. By adopting more patient-centred approaches, healthcare providers can enhance patient satisfaction and improve treatment adherence, ultimately leading to better patient outcomes and quality of life.

Inter-grader reliability in the Danish screening programme for diabetic retinopathy

PURPOSE

The Danish Registry of Diabetic Retinopathy includes information from >200 000 patients who attends diabetic retinopathy (DR) screening in Denmark. Screening of patients with uncomplicated type 2 diabetes is often performed by practicing ophthalmologists, while patients with type 1 and complicated type 2 diabetes attends screening at hospitals. We performed a clinical reliability study of retinal images from Danish screening facilities to explore the inter-grader agreement between the primary screening ophthalmologist and a blinded, certified grader.

METHODS

Invitations to participate were sent to screening facilities across Denmark. The primary grader uploaded fundus photographs with information on estimated level of DR (International Clinical Diabetic Retinopathy scale as 0 [no DR], 1-3 [mild, moderate or severe nonproliferative DR {NPDR}], or 4 [proliferative DR {PDR}]), region of screening, image style, and screening facility. Images were then regraded by a blinded, certified, secondary grader. Weighted kappa analysis was performed to evaluate agreement.

RESULTS

Fundus photographs from 230 patients (458 eyes) were received from practicing ophthalmologists (52.6%) and hospital-based grading centres (47.4%) from all Danish regions. Reported levels of DR by the primary graders were 66.8%, 12.2%, 13.1%, 1.3% and 5.5% for DR levels 0-4. The overall agreement between primary and secondary graders was 93% (κ = 0.83). Based on screening facility agreement was 96% (κ = 0.89) and 90% (κ = 0.76) for practicing ophthalmologists and hospital-based graders.

CONCLUSION

In this nationwide study, we observed a high overall inter-grader agreement and based on this, it is reasonable to assume that reported DR gradings in the screening programme in Denmark, accurately reflect the truth.

Bariatric surgery in individuals with type 2 diabetes is not associated with short or long-term risk of diabetic retinopathy progression: results from a nationwide cohort study

AIMS

Bariatric surgery is used to induce weight loss and glycemic stability in type 2 diabetes (T2D). It has been a concern that this may lead to early worsening of diabetic retinopathy (DR) due to a rapid decline in HbA1c. In this study, we evaluated the risk of short and long-term DR development and need for ocular intervention in an entire nation of individuals with T2D undergoing bariatric surgery.

METHODS

The study comprised a national, register-based cohort of individuals with T2D screened for DR. Cases were matched by age, sex and DR level at the date of surgery (index date) with non-bariatric controls. We extracted information on DR levels, in- and outpatient treatments, pharmaceutical prescriptions and laboratory values. We evaluated worsening of DR (incident and progressive DR) at follow-up (6 and 36 months).

RESULTS

Amongst 238,967 individuals with T2D, who attended diabetic eye screening, we identified 553 that underwent bariatric surgery (0.2%) and 2677 non-bariatric controls. Median age was 49 years, and 63% were female. Cases had more comorbidities, lower HbA1c as well as more frequent use of glucose-lowering and antihypertensive medication than controls at index date. In a fully adjusted logistic regression model, the risk of DR worsening for cases was not significantly different compared to controls, neither short-term (OR 0.41 [CI 95% 0.13; 1.33], p = 0.14) nor long-term (OR 0.64 [CI 95% 0.33; 1.24], p = 0.18).

CONCLUSIONS

In this nationwide study, bariatric surgery did not associate with increased risk of short- or long-term DR worsening.

Retinal vein occlusion as an age-dependent marker of incident dementia in a long-term Danish national cohort

PURPOSE

The aim of this study was to investigate retinal vein occlusion (RVO) as an independent marker of incident dementia.

METHODS

In a prospective nationwide cohort study, we identified 2 225 568 individuals through the Danish national health registers. Individuals older than 65 years, without unspecified retinal vascular occlusion or dementia were included from 1998 to 2020 and followed until 2022. We calculated the incidence rate (IR) and performed a Cox regression analysis with a hazard ratio (HR) and 95% confidence interval (CI) for RVO (exposure) as a marker of all-cause dementia adjusted for systemic comorbidity.

RESULTS

We identified 19 669 individuals with RVO who had a higher prevalence of systemic comorbidity at inclusion compared to those without RVO (n = 2 185 483). We performed a Cox regression analysis for age-dependent exposure due to non-proportional hazards in the pre-planned analysis. Exposed individuals younger than 75 years had an increased risk of all-cause dementia (adjusted HR 1.09, 95% CI 1.01-1.18), whereas individuals older than 75 years had a decreased risk of all-cause dementia (adjusted HR 0.92, 95% CI 0.86-0.98).

CONCLUSION

Individuals with RVO had an age-dependent risk of dementia, with a 9% increased risk in individuals with RVO younger than 75 years and an 8% decreased risk in individuals older than 75 years at the time of exposure.

Retinal main vessel calibers and systemic markers for long-term development of proliferative diabetic retinopathy

PURPOSE

To evaluate if retinal vascular calibers and systemic risk factors in patients with no or minimal diabetic retinopathy (DR) can predict risk of long-term progression to proliferative diabetic retinopathy (PDR).

METHODS

This was a matched case-control study of patients with diabetes having no or minimal DR at baseline with (cases) or without (controls) subsequent development of PDR. We collected six-field, 45-degree retinal images, demographic and clinical data from the Funen Diabetes Database.

RESULTS

We included 52 eyes from 39 cases and 107 eyes from 89 controls matched on sex, age, type of diabetes, time from first to last screening episode and baseline DR level. Cases had higher HbA1c (73 vs. 55 mmoL/moL; p < 0.001), triglycerides (1.32 vs. 1.16 mmoL/L; p = 0.02) and longer duration of diabetes (19 vs. 14 years; p = 0.01), but the groups did not differ in calibers of retinal arterioles (229 vs. 227 μm; p = 0.49), venules (289 vs. 290 μm; p = 0.83) or the arterio-to-venule ratio (0.78 vs. 0.77; p = 0.86).In a multivariable logistic regression model with cluster robust standard error, HbA1c (OR 1.54 per 10 mmoL/moL; 95%-CI: 1.15-2.07; p = 0.004), triglyceride (OR 1.39 per 1 mmoL/L; 95%-CI: 1.03-1.86; p = 0.03) and duration of diabetes (OR 1.09 per year; 95%-CI: 1.03-1.16; p = 0.003) were independent risk factors for PDR.

CONCLUSION

Retinal vascular calibers did not predict long-term development of PDR in contrast to well-established risk factors like HbA1c, triglyceride and duration of diabetes.

Longitudinal bidirectional associations between diabetic retinopathy and diagnosed depression: Results from a Danish nationwide registry-based cohort study

OBJECTIVE

Diabetic retinopathy (DR) is a feared complication and a leading course of visual impairment, but the connection between DR and depression including the direction has never been studied in a nationwide cohort. We aimed to assess, whether the associations between DR and diagnosed depression are bidirectional.

METHODS

We performed a national register-based cohort study of individuals with type 2 diabetes, who attended diabetic eye screening between January 2013 and June 2022. Level of DR was extracted from the Danish Registry of Diabetic Retinopathy. The severity of DR was assessed according to the International Clinical Diabetic Retinopathy severity scale. Diagnosed depression was ascertained by physician diagnostic codes of unipolar depression (F32), recurrent depression (F33) or dysthymia (F34.1) from the Danish National Patient Register. We estimated presence of diagnosed depression according to DR level at index date and risk of diagnosed depression during follow-up using multivariable logistic and Cox regression, respectively. Secondly, we assessed whether diagnosed depression at index date could predict incident DR.

RESULTS

We included 240,893 individuals with type 2 diabetes with baseline rates of diagnosed depression ranging from 5.2 to 6.0 % for DR level 1-4. At index date, individuals with type 2 diabetes and DR were less likely to have a history of diagnosed depression (multivariable adjusted OR, 0.77 [95 % CI 0.73-0.82]). In 226,523 individuals with type 2 diabetes followed for 1,159,755 person-years, 1.7 % developed at least one episode of diagnosed depression. In a model adjusted for age and sex, individuals with DR at index date had an increased risk of incident diagnosed depression compared to those without DR (HR 1.25 [95 % CI 1.16-1.36]). Adjusting for marital status, use of glucose-, lipid- and blood pressure lowering medication, HbA1c, diabetic neuropathy and Charlson comorbidity index waived the above risk (multivariable adjusted HR 1.02 [95 % CI 0.93-1.12]). Furthermore a previous history of diagnosed depression was not associated with increased risk of incident DR (multivariable adjusted HR 0.89 [95 % CI 0.77-1.03]).

CONCLUSION

In this nationwide cohort study, individuals with DR at first screening were 23 % less likely to have a history of depression, but our data did not support a bidirectional association between DR and depression. Selection bias may have occurred as diagnosed depression is a known barrier for attending DR-screening.

Intravitreal Vascular Endothelial Growth Factor Inhibitor Therapy in Denmark and 5-Year Projections

This cohort study examines the use of intravitreal injections of vascular endothelial growth factor inhibitor in Denmark from 2007 through 2022 and forecasts future demand for this therapy.

Five-Year Incidence of Proliferative Diabetic Retinopathy and Associated Risk Factors in a Nationwide Cohort of 201 945 Danish Patients with Diabetes

Purpose

To evaluate the proliferative diabetic retinopathy (PDR) progression rates and identify the demographic and clinical characteristics of patients who later developed PDR compared with patients who did not progress to that state.

Design

A national 5-year register-based cohort study including 201 945 patients with diabetes.

Subjects

Patients with diabetes who had attended the Danish national screening program (2013-2018) for diabetic retinopathy (DR).

Methods

We used the first screening episode as the index date and included both eyes of patients with and without subsequent progression of PDR. Data were linked with various national health registries to investigate relevant clinical and demographic parameters. The International Clinical Retinopathy Disease Scale was used to classify DR, with no DR as level 0, mild DR as level 1, moderate DR as level 2, severe DR as level 3, and PDR as level 4.

Main Outcome Measures

Hazard ratios (HRs) for incident PDR for all relevant demographic and clinical parameters and 1-, 3-, and 5-year incidence rates of PDR according to baseline DR level.

Results

Progression to PDR within 5 years was identified in 2384 eyes of 1780 patients. Proliferative diabetic retinopathy progression rates from baseline DR level 3 at 1, 3 and 5 years were 3.6%, 10.9%, and 14.7%, respectively. The median number of visits was 3 (interquartile range, 1-4). Progression to PDR was predicted in a multivariable model by duration of diabetes (HR, 4.66 per 10 years; 95% confidence interval [CI], 4.05-5.37), type 1 diabetes (HR, 9.61; 95% CI, 8.01-11.53), a Charlson Comorbidity Index score of > 0 (score 1: HR, 4.62; 95% CI, 4.14-5.15; score 2: HR, 2.28; 95% CI, 1.90-2.74; score ≥ 3: HR, 4.28; 95% CI, 3.54-5.17), use of insulin (HR, 5.33; 95% CI, 4.49-6.33), and use of antihypertensive medications (HR, 2.23; 95% CI, 1.90-2.61).

Conclusions

In a 5-year longitudinal study of an entire screening nation, we found increased risk of PDR with increasing baseline DR levels, longer duration of diabetes, type 1 diabetes, systemic comorbidity, use of insulin, and blood pressure-lowering medications. Most interestingly, we found lower risk of progression from DR level 3 to PDR compared with that in previous studies.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Cardiovascular morbidity and all-cause mortality in patients with retinal vein occlusion: a Danish nationwide cohort study

BACKGROUND/AIMS

Associations between retinal vein occlusion (RVO) and subsequent cardiovascular disease (CVD) or mortality have not been evaluated in a recent cohort, after novel therapeutic options have increased referrals for treatment of the condition. We aimed to evaluate overall and subtype-stratified risk of CVD and all-cause mortality following RVO and assess any alterations after the introduction of angiostatic therapy in Denmark in 2011.

METHODS

This nationwide, registry-based cohort study from 1998 to 2018 evaluated 4 194 781 individuals. Hazard ratios (HRs) were reported for RVO as an overall measure and subclassified as branch and central RVO.

RESULTS

Patients with RVO (n=15 665) were median 71.8 years old at the time of exposure and 50.7% were women. RVO associated with incident CVD (adjusted HR 1.13, 95% CI 1.09 to 1.17) but not mortality (adjusted HR 1.00, 95% CI 0.97 to 1.03). Almost similar risks of CVD were found for patients with branch and central RVO (adjusted HRs 1.14, 95% CI 1.03 to 1.25, and 1.12, 95% CI 1.00 to 1.25, respectively), but only patients with central RVO exhibited increased mortality (adjusted HR 1.12, 95% CI 1.04 to 1.21). Risk of CVD, especially non-ischaemic, was higher for patients diagnosed after 2011 (adjusted HRs 1.24, 95% CI 1.15 to 1.33 vs 1.06, 95% CI 1.01 to 1.12).

CONCLUSION

In a cohort of the Danish population aged 40 years or more, patients with RVO had a 13% increased risk of incident CVD compared with unexposed individuals. Risk of CVD was increased after 2011, when intravitreal angiostatic treatment was introduced and referral practices altered.

Retinal artery occlusion does not act as an independent marker of upcoming dementia: results from a Danish 20-year cohort study

PURPOSE

Retinal artery occlusion (RAO) is a vision threatening disease associated with cerebral vascular dysfunction, which may reflect initial signs of cerebral pathology. Early detection of patients in risk of dementia could allow for preventative treatment. Hence, this study aimed to investigate RAO as an independent biomarker of incident dementia.

METHODS

This study was a nationwide, 20-year longitudinal cohort study in Denmark with inclusion from 1998 to 2020 and follow up until the end of 2022. We identified 2 205 159 individuals aged 65 or older through the Danish national health registers and monitored RAO (exposure) and dementia (outcome) status. We calculated incidence rate and performed a Cox regression analysis with hazard ratio (HR) and 95% confidence interval (CI) for RAO as a marker of dementia in a crude, a semi-adjusted (age and sex), and a fully adjusted model (furthermore adjusted for marital status and systemic comorbidity.) RESULTS: We identified 8 863 individuals with RAO. Incidence rates were higher among exposed compared to unexposed individuals (12.28 and 8.18 per 1000 person-years at risk, respectively). Individuals with RAO were more likely to be male and older at inclusion, to have hypertension, dyslipidaemia, cardiovascular disease, chronic kidney disease, and diabetes (p < 0.001). RAO was not associated with all-cause dementia in the crude analysis (HR 1.07 CI [1.00-1.17]) or in the fully adjusted analysis (HR 0.98 CI [0.91-1.06].

CONCLUSION

Although individuals with RAO had a higher incidence of dementia compared to unexposed individuals, these associations were lost when confounders were taken into account.

Diabetic retinopathy is a predictor of chronic respiratory failure: A nationwide register-based cohort study

Purpose

Diabetic retinopathy (DR) is a hypoxic retinal disease, but so far, the association with systemic hypoxia is poorly understood. Hence, the aim of this study was to evaluate cross-sectional and longitudinal associations between DR and chronic respiratory failure (CRF) in a national cohort.

Design

Cross-sectional and 5-year longitudinal register-based cohort study.

Methods

Between 2013 and 2018, we included patients with diabetes from the Danish Registry of Diabetic Retinopathy, who were each age and sex matched with five controls without diabetes. At index date, the prevalence of CRF was compared between cases and controls, and the longitudinal relationship between DR and CRF was assessed in a five-year follow-up.

Results

At baseline, we identified 1,980 and 9,990 patients with CRF among 205,970 cases and 1,003,170 controls. The prevalence of CRF was higher among cases than controls (OR 1.75, 95% CI 1.65-1.86), but no difference between cases with and without DR was found.During follow-up, we identified 1,726 and 5,177 events of CRF among cases and controls, respectively. The incidence of CRF was higher among both cases with and without DR compared to controls (DR level 0: HR 1.24, 95% CI 1.16-1.33, DR level 1-4: HR 1.86, 95% CI 1.63-2.12), and higher among cases with DR compared to cases without DR (HR 1.54, 95% CI 1.38-1.72).

Conclusion

In this study based on nationwide data, we found an increased risk of present and incident CRF in patients with diabetes with or without DR, and we identified DR as a predictor of future CRF.

Prayer and meditation practices in the early COVID-19 pandemic: A nationwide survey among Danish pregnant women. The COVIDPregDK study

BACKGROUND

The emergence of the COVID-19 pandemic and the derived changes in maternity care have created stress and anxiety among pregnant women in different parts of the world. In times of stress and crisis, spirituality, including spiritual and religious practices, may increase.

OBJECTIVE

To describe if the COVID-19 pandemic influenced pregnant women's considerations and practises of existential meaning-making and to investigate such considerations and practices during the early pandemic in a large nationwide sample.

METHODS

We used survey data from a nationwide cross-sectional study sent to all registered pregnant women in Denmark during April and May 2020. We used questions from four core items on prayer and meditation practices.

RESULTS

A total of 30,995 women were invited, of whom 16,380 participated (53%). Among respondents, we found that 44% considered themselves believers, 29% confirmed a specific form of prayer, and 18% confirmed a specific form of meditation. In addition, most respondents (88%) reported that the COVID-19 pandemic had not influenced their responses.

CONCLUSION

In a nationwide Danish cohort of pregnant women, existential meaning-making considerations and practices were not changed due to the COVID-19 pandemic. Nearly one in two study participants described themselves as believers, and many practised prayer and/or meditation.

Presence and development of diabetic retinopathy in 153 238 patients with type 2 diabetes in the Danish Registry of Diabetic Retinopathy

PURPOSE

The purpose of the study was to evaluate the prevalence and incidence of diabetic retinopathy (DR) along with associated markers in patients with type 2 diabetes in the Danish DR-screening programme.

METHODS

We included all persons with type 2 diabetes in the Danish Registry of Diabetic Retinopathy, who had attended at least one episode of DR screening in 2013-2018. DR was classified as levels 0-4 indicating increasing severity. Data were linked with various national health registries to retrieve information on diabetes duration, marital status, comorbidity and systemic medication.

RESULTS

Among 153 238 persons with type 2 diabetes, median age and duration of diabetes were 66.9 and 5.3 years and 56.4% were males. Prevalence and 5-year incidences of DR, 2-step-or-more progression of DR and progression to proliferative DR (PDR) were 8.8%, 3.8%, 0.7% and 0.2%, respectively. In multivariable models, leading markers of incident DR and progression to PDR were duration of diabetes (HR 1.98, 95% CI 1.87-2.09; HR 2.89, 95% CI 2.34-3.58 per 10 years of duration) and use of insulin (HR 1.88, 95% CI 1.76-2.01; HR 2.40, 95% CI 1.84-3.13), while the use of cholesterol-lowering medicine was a protecting marker (HR 0.87, 95% CI 0.81-0.93; HR 0.70, 95% CI 0.52-0.93). From 2013 to 2015, 3-year incidence rates of PDR decreased from 1.22 to 0.45 events per 1000 person-years.

CONCLUSION

Nationally, among Danish individuals with type 2 diabetes attending DR screening, we identified duration of diabetes and use of insulin as the most important predictor for the development of DR, while cholesterol-lowering medicine was a protective factor.

Vascular endothelial growth factor inhibition in retinal vein occlusion does not associate with cardiovascular morbidity and mortality

PURPOSE

Intravitreal treatment with vascular endothelial growth factor (VEGF) inhibitors have proven safe in clinical trials, but often on selected patient groups and without statistical power to investigate rare safety events. Data on anti-VEGF treatment in retinal vein occlusion (RVO) patients are sparsely represented and studies providing population-based, long-term follow-up are needed to assess the risks in a nationwide setting. We aimed to evaluate the association between treatment with anti-VEGF and risk of incident cardiovascular disease (CVD) and all-cause mortality in patients with RVO, and whether this association was affected by selected risk factors.

DESIGN

Cohort study from January 2012 to December 2018 using Danish nationwide registries linked on an individual level. Subjects, Participants, and/or Controls: RVO patients (n=7235), exposed (n=3508) and unexposed (n=3727) to anti-VEGF, aged 40 years or more, alive and living in Denmark. Methods, Intervention, or Testing: Cox proportional hazards analysis evaluating the effect of intravitreal VEGF inhibitory treatment on incident CVD and all-cause mortality.

MAIN OUTCOME MEASURES

A pre-defined analysis plan specified primary outcomes as hazard ratios (HR) of a composite CVD endpoint and all-cause mortality in patients treated with anti-VEGF compared with untreated. Secondary outcomes included cumulative dose analysis, HRs on subgroups of CVD and stratified analyses evaluating the effect of sex, age, diabetes, intensive treatment, and pre-existing CVD on the HRs.

RESULTS

We found no increased risk of composite CVD (HR 1.07, 95% CI 0.89 to 1.29) or all-cause mortality (HR 0.88, 95% CI 0.77 to 1.00) in RVO patients treated with anti-VEGF. In the secondary analyses we found no dose-response relationship. We found an increased risk of intracranial hemorrhage (HR 1.66, 95% CI 1.02 to 2.71), but no increased risks in remaining subgroups of CVD. We found no increased risk associated with selected pre-disposing risk factors, and no increased risk in patients with pre-existing CVD.

CONCLUSIONS

Treatment with anti-VEGF in RVO patients is safe, when evaluated in a nationwide, population-based setting. An increased risk of intracranial hemorrhage might be present, but cannot be reliably quantified and should be further elucidated by larger population-based studies including all indications for anti-VEGF treatment.

Bidirectional 5-year risks of diabetic retinopathy, glaucoma and/or ocular hypertension: Results from a national screening programme

PURPOSE

We aimed to investigate if diabetic retinopathy (DR), glaucoma and/or ocular hypertension (OHT) are prospectively linked, as previous studies have proposed cross-sectional associations, but longitudinal data from larger cohorts are lacking.

METHODS

We performed a bidirectional 5 years prospective, registry-based cohort study. We extracted data from national registers, including the Danish Registry of Diabetic Retinopathy, the Danish Civil Registration System, the Danish National Patient Register and the Danish National Prescription Registry. DR level was defined by the highest level of the two eyes. Glaucoma and/or OHT was defined by diagnostic codes (H40*) or at least three redeemed prescriptions of glaucoma medication (S01E*) within 1 year. We included 205 970 persons with diabetes and 1 003 170 age- and gender-matched non-diabetes controls. Exposures were level-specific DR (i) and glaucoma and/or OHT (ii), and outcomes were hazard ratios (HRs) for 5 years incident glaucoma and/or OHT (i) and DR (ii).

RESULTS

Persons with diabetes were more likely to develop glaucoma and/or OHT (multivariable adjusted HR 1.11, 95% CI 1.06-1.15), but this did not depend on the level of DR. In persons with diabetes, those with glaucoma and/or OHT were more likely to develop DR (multivariable adjusted HR 1.12, 95% CI 1.03-1.23) within 5 years.

CONCLUSION

In a national cohort, diabetes associated with a little higher risk of upcoming glaucoma and/or OHT, and, inversely, the presence of the latter predicted a higher risk of incident DR. Nevertheless, our data do not seem to justify including glaucoma evaluation in the national Danish DR-screening programme.

Attendance in a national screening program for diabetic retinopathy: a population-based study of 205,970 patients

AIMS

A nationwide diabetic retinopathy (DR) screening program has been established in Denmark since 2013. We aimed to perform an evaluation of adherence to DR screenings and to examine whether non-adherence was correlated to DR progression.

METHODS

The population consisted of a register-based cohort, who participated in the screening program from 2013 to 2018. We analyzed age, gender, marital status, DR level (International Clinical DR severity scale, none, mild-, moderate-, severe non-proliferative DR (NPDR) and proliferative DR (PDR)), comorbidities and socioeconomic factors. The attendance pattern of patients was grouped as either timely (no delays > 33%), delayed (delays > 33%) or one-time attendance (unexplained).

RESULTS

We included 205,970 patients with 591,136 screenings. Rates of timely, delayed and one-time attendance were 53.0%, 35.5% and 11.5%, respectively. DR level at baseline was associated with delays (mild-, moderate-, severe NPDR and PDR) and one-time attendance (moderate-, severe NPDR and PDR) with relative risk ratios (RRR) of 1.68, 2.27, 3.14, 2.44 and 1.18, 2.07, 1.26, respectively (P < 0.05). Delays at previous screenings were associated with progression to severe NPDR or PDR (hazard ratio (HR) 2.27, 6.25 and 12.84 for 1, 2 and 3+ delays, respectively). Any given delay doubled the risk of progression (HR 2.28).

CONCLUSIONS

In a national cohort of 205,970 patients, almost half of the patients attended DR screening later than scheduled or dropped out after first screening episode. This was, in particular, true for patients with any levels of DR at baseline. DR progression in patients with delayed attendance, increased with the number of missed appointments.

Diabetic Retinopathy Predicts Risk of Alzheimer’s Disease: A Danish Registry-Based Nationwide Cohort Study

Background:

Retinal neurodegeneration is evident in early diabetic retinopathy (DR) which may be associated with other neurodegenerative diseases like Alzheimer's disease (AD).

Objective:

To investigate diabetes and DR as a risk marker of present and incident AD.

Methods:

A register-based cohort study was performed. We included 134,327 persons with diabetes above 60 years of age, who had attended DR screening, and 651,936 age- and gender-matched persons without diabetes.

Results:

At baseline, the prevalence of AD was 0.7% and 1.3% among patients with and without diabetes, respectively. In a multivariable regression model, patients with diabetes were less likely to have AD at baseline (adjusted OR 0.63, 95% CI 0.59–0.68). During follow-up, incident AD was registered for 1473 (0.35%) and 6,899 (0.34%) persons with and without diabetes, respectively. Compared to persons without diabetes, persons with diabetes and no DR had a lower risk to develop AD (adjusted HR 0.87, 95% CI 0.81–0.93), while persons with diabetes and DR had higher risk of AD (adjusted HR 1.24, 95% CI 1.08–1.43). When persons with diabetes and no DR were used as references, a higher risk of incident AD was observed in persons with DR (adjusted HR 1.34, 95% CI 1.18–1.53).

Conclusion:

Individuals with diabetes without DR were less likely to develop AD compared to persons without diabetes. However, individuals with DR had a 34% higher risk of incident AD, which raise the question whether screening for cognitive impairment should be done among individuals with DR.

Diabetic retinopathy as a potential marker of Parkinson's disease: a register-based cohort study

Neurodegeneration is an early event in the pathogenesis of diabetic retinopathy, and an association between diabetic retinopathy and Parkinson’s disease has been proposed. In this nationwide register-based cohort study, we investigated the prevalence and incidence of Parkinson’s disease among patients screened for diabetic retinopathy in a Danish population-based cohort. Cases (n = 173 568) above 50 years of age with diabetes included in the Danish Registry of Diabetic Retinopathy between 2013 and 2018 were matched 1:5 by gender and birth year with a control population without diabetes (n = 843 781). At index date, the prevalence of Parkinson’s disease was compared between cases and controls. To assess the longitudinal relationship between diabetic retinopathy and Parkinson’s disease, a multivariable Cox proportional hazard model was estimated. The prevalence of Parkinson’s disease was 0.28% and 0.44% among cases and controls, respectively. While diabetic retinopathy was not associated with present (adjusted odds ratio 0.93, 95% confidence interval 0.72–1.21) or incident Parkinson’s disease (adjusted hazard ratio 0.77, 95% confidence interval 0.56–1.05), cases with diabetes were in general less likely to have or to develop Parkinson’s disease compared to controls without diabetes (adjusted odds ratio 0.79, 95% confidence interval 0.71–0.87 and adjusted hazard ratio 0.88, 95% confidence interval 0.78–1.00). In a national cohort of more than 1 million persons, patients with diabetes were 21% and 12% were less likely to have prevalent and develop incident Parkinson’s disease, respectively, compared to an age- and gender-matched control population without diabetes. We found no indication for diabetic retinopathy as an independent risk factor for incident Parkinson’s disease.

The COVIDPregDK Study: A national survey on pregnancy during the early COVID-19 pandemic in Denmark

AIM

We aimed to describe the aim, data collection and content from a survey completed among pregnant women during the first peak of the COVID-19 pandemic in Denmark.

METHODS

The declaration of the COVID-19 pandemic in early 2020 challenged pregnant women's mental well-being due to a concern for their unborn child and their need for healthcare services through pregnancy and birth. To explore how the COVID-19 pandemic and the intensified measures such as the lockdown of Denmark impacted pregnant women's well-being and mental health, we conducted a questionnaire survey in the spring of 2020 when the COVID-19 pandemic was at its first peak, and the consequences for pregnant women and the unborn child were very uncertain. All women residing in Denmark and registered with an ongoing pregnancy on 24 April 2020 were invited to participate. The questionnaire included background information, variables on COVID-19 symptoms and validated batteries of questions on loneliness, anxiety, stress, quality of life, meditation and prayers. Additional questions were included to examine concerns related to pregnancy and childbirth during the pandemic.

COHORT CHARACTERISTICS

Almost 18,000 women answered the questionnaire, which represents 60% of all invited women who experienced a national lockdown for the first time. Their median age was 30 years, and they were more likely to be multiparous.

CONCLUSIONS

Data from the COVIDPregDK Study will enable us to gain valuable knowledge on how the pandemic, the intensified measures from the health authorities and the national lockdown affected pregnant women's mental health and their concerns during the COVID-19 pandemic.

Concerns about transmission, changed services and place of birth in the early COVID-19 pandemic: a national survey among Danish pregnant women. The COVIDPregDK study

BACKGROUND

The outbreak of the COVID-19 pandemic caused great uncertainty about causes, treatment and mortality of the new virus. Constant updates of recommendations and restrictions from national authorities may have caused great concern for pregnant women. Reports suggested an increased number of pregnant women choosing to give birth at home, some even unassisted ('freebirth') due to concerns of transmission in hospital or reduction in birthplace options. During April and May 2020, we aimed to investigate i) the level of concern about coronavirus transmission in Danish pregnant women, ii) the level of concern related to changes in maternity services due to the pandemic, and iii) implications for choice of place of birth.

METHODS

We conducted a nationwide cross-sectional online survey study, inviting all registered pregnant women in Denmark (n = 30,009) in April and May 2020.

RESULTS

The response rate was 60% (n = 17,995). Concerns of transmission during pregnancy and birth were considerable; 63% worried about getting severely ill whilst pregnant, and 55% worried that virus would be transmitted to their child. Thirtyeight percent worried about contracting the virus at the hospital. The most predominant concern related to changes in maternity services during the pandemic was restrictions on partners' attendance at birth (81%). Especially nulliparous women were concerned about whether cancelled antenatal classes or fewer physical midwifery consultations would affect their ability to give birth or care for their child postpartum.. The proportion of women who considered a home birth was equivalent to pre-pandemic home birth rates in Denmark (3%). During the temporary discontinue of public home birth services, 18% of this group considered a home birth assisted by a private midwife (n = 125), and 6% considered a home birth with no midwifery assistance at all (n = 41).

CONCLUSION

Danish pregnant womens' concerns about virus transmission to the unborn child and worries about contracting the virus during hospital appointments were considerable during the early pandemic. Home birth rates may not be affected by the pandemic, but restrictions in home birth services may impose decisions to freebirth for a small proportion of the population.

SARS-CoV-2 infection in pregnancy in Denmark-characteristics and outcomes after confirmed infection in pregnancy: A nationwide, prospective, population-based cohort study

Introduction

Assessing the risk factors for and consequences of infection with severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) during pregnancy is essential to guide clinical care. Previous studies on SARS‐CoV‐2 infection in pregnancy have been among hospitalized patients, which may have exaggerated risk estimates of severe outcomes because all cases of SARS‐CoV‐2 infection in the pregnant population were not included. The objectives of this study were to identify risk factors for and outcomes after SARS‐CoV‐2 infection in pregnancy independent of severity of infection in a universally tested population, and to identify risk factors for and outcomes after severe infection requiring hospital admission.

Material and methods

This was a prospective population‐based cohort study in Denmark using data from the Danish National Patient Register and Danish Microbiology Database and prospectively registered data from medical records. We included all pregnancies between March 1 and October 31, 2020 and compared women with a positive SARS‐CoV‐2 test during pregnancy to non‐infected pregnant women. Cases of SARS‐CoV‐2 infection in pregnancy were both identified prospectively and through register linkage to ensure that all cases were identified and that cases were pregnant during infection. Main outcome measures were pregnancy, delivery, maternal, and neonatal outcomes. Severe infection was defined as hospital admission due to coronavirus disease 2019 (COVID‐19) symptoms.

Results

Among 82 682 pregnancies, 418 women had SARS‐CoV‐2 infection during pregnancy, corresponding to an incidence of 5.1 per 1000 pregnancies, 23 (5.5%) of which required hospital admission due to COVID‐19. Risk factors for infection were asthma (odds ratio [OR] 2.19, 95% CI 1.41–3.41) and being foreign born (OR 2.12, 95% CI 1.70–2.64). Risk factors for hospital admission due to COVID‐19 included obesity (OR 2.74, 95% CI 1.00–7.51), smoking (OR 4.69, 95% CI 1.58–13.90), infection after gestational age (GA) 22 weeks (GA 22–27 weeks: OR 3.77, 95% CI 1.16–12.29; GA 28–36 weeks: OR 4.76, 95% CI 1.60–14.12), and having asthma (OR 4.53, 95% CI 1.39–14.79). We found no difference in any obstetrical or neonatal outcomes.

Conclusions

Only 1 in 20 women with SARS‐CoV‐2 infection during pregnancy required admission to hospital due to COVID‐19. Risk factors for admission comprised obesity, smoking, asthma, and infection after GA 22 weeks. Severe adverse outcomes of SARS‐CoV‐2 infection in pregnancy were rare.

Inverse Cross-sectional and Longitudinal Relationships between Diabetic Retinopathy and Obstructive Sleep Apnea in Type 2 Diabetes

Purpose

Design

Participants

Methods

Main Outcome Measures

Results

Conclusions

Interactions between ocular and systemic disease using national register-based data in the Danish Excellence Centre in Ophthalmic Epidemiology (DECODE-EYE): study perspective

PURPOSE

The Danish Excellence Centre in Ophthalmic Epidemiology (DECODE-EYE) is a national research collaboration formed in order to study the real-life interaction between ocular and systemic disease based on the entire Danish population. Here, we aim to describe the study design and the methodology, which will be used.

METHODS

We will extract data from various healthcare registers and databases including the Danish Civil Registration System (unique personal identifier), the Danish National Patient Register (inpatient and outpatient visits), the Danish National Prescription Registry (redeemed prescription drugs), the National Health Service Register (data on health services in primary health care), the Danish Register of Cause of Death (data on cause of death), Statistics Denmark (demographic and socioeconomic data), the Danish Registry of Diabetic Retinopathy (level of diabetic retinopathy (DR) in diabetes patients) and the database of the Danish Association of the Blind (date and cause of blindness). Relevant registers will be linked by the unique personal identifier, and associations will be examined cross-sectional and/or longitudinally, in principle in 1:5 age- and gender-matched case-control cohort studies.

CONCLUSION

Denmark has a strong tradition in register-based healthcare research, given a high number of validated national registers and databases. DECODE-EYE will provide Danish, large-scale data on associations between ocular and systemic disease. With a target population of 5.8 million individuals, twelve separate studies (Protocols A-L) have initially been designed to be studied in the upcoming years. These will provide novel data on interactions between systemic disease and relevant ophthalmological end-points like blindness, DR, glaucoma, corneal disease, retinal vascular disease, cataract and intravitreal angiostatic treatment.

Long-Term Opioid Therapy in Spine Center Outpatients: Protocol for the Spinal Pain Opioid Cohort (SPOC) Study

Background

Spinal pain is the leading cause of patient-years lived with chronic pain and disability worldwide. Although opioids are well documented as an effective short-term pain-relieving medication, more than a few weeks of treatment may result in a diminishing clinical effect as well as the development of addictive behavior. Despite recognition of opioid addiction in pain patients as a major problem commonly experienced in the clinic, no reference material exists on the scope of long-term problems in novel opioid users and the link to clinical outcomes.

Objective

The main aims of this study are to describe baseline and follow-up characteristics of the Spinal Pain Opioid Cohort (SPOC), to evaluate the general use of opioids in spinal pain when an acute pain episode occurs, and to demonstrate the prevalence of long-term opioid therapy (LTOT).

Methods

Prospective clinical registry data were collected from an outpatient spine center setting during 2012-2013 including patients with a new spinal pain episode lasting for more than 2 months, aged between 18 and 65 years who had their first outpatient visit in the center. Variables include demographics, clinical data collected in SpineData, the Danish National Patient Register, and The Danish National Prescription Registry. The primary outcome parameter is long-term prescription opioid use registered from 4 years before the first spine center visit to 5 years after.

Results

This is an ongoing survey. It is estimated that more than 8000 patients fulfill the SPOC inclusion criteria. In 2019, we began the intellectual process of identifying the most relevant supplementary data available from the wide range of existing national registries available in Denmark. We have now begun merging SpineData with relevant opioid data from Danish national registers and will continue to extract data up to 2021-2022. We will also be looking at data regarding somatic or psychiatric hospitalization patterns, patient usage of health care resources, as well as their working status and disability pensions.

Conclusions

To our knowledge, this survey will be the first to document the scope of long-term problems regarding LTOT and opioid addiction following new spinal pain episodes and comparing descriptive follow-up data between substance users and nonusers.

Trial Registration

ISRCTN Registry ISRCTN69685117; http://www.isrctn.com/ISRCTN69685117

International Registered Report Identifier (IRRID)

DERR1-10.2196/21380

Obstetric oxytocin exposure and ADHD and ASD among Danish and Finnish children

Background

Some studies have indicated an increased risk of attention deficit hyperactivity disorder (ADHD) and a small, sex-specific association with autism spectrum disorder (ASD) among children prenatally exposed to obstetric oxytocin. Since oxytocin is widely used in the obstetric ward, these potentially deleterious effects are of concern. Thus, we aimed to examine whether obstetric oxytocin treatment for labour induction or augmentation is associated with ADHD and ASD in offspring born in a two-country design based on data from Denmark and Finland.

Methods

This population-based study used data from national registers in Denmark and Finland. Singletons born in Denmark 2000–10 (n = 577 380) and Finland 1991–2010 (n = 945 543), who survived infancy, were followed until 31 December 2015. ADHD and ASD were defined using diagnostic codes. For ADHD, we also included information on prescribed and redeemed ADHD medication in the definition. Hazards ratios (HRs) with 95% confidence intervals (CI), modelled with age as the underlying time scale, were calculated to estimate the associations.

Results

Oxytocin was used in 31% and 46% of the included deliveries in Denmark and Finland, respectively. In crude analyses, prenatal oxytocin was associated with an approximately 20% increased risk of ADHD and ASD, but confounder adjustment attenuated the association. The adjusted HR was 1.03, 95% CI 1.01–1.05, for ADHD and 1.05, 95% CI 1.02–1.08, for ASD. The results were similar in across country and gender.

Conclusions

We found an association between synthetic oxytocin and ADHD or ASD which is unlikely to reflect a causal association and thus should not support the concern of clinical use. Our results help to allay concerns of obstetric use of oxytocin causing ADHD or ASD.

Labor augmentation during birth and later cognitive ability in young adulthood

PURPOSE

Synthetic oxytocin for labor augmentation during birth has been linked to negative neurodevelopment effects in children. We examined whether maternal labor augmentation was associated with lower cognitive ability in young adulthoods.

PATIENTS AND METHODS

We identified 330,107 individuals (96.6% were men), with noninduced labor and with a cognitive ability test score, the Børge Priens Prøve (BPP) score, from draft board examinations in 1995-2015 (mean age, 18.8 years). Information on maternal labor augmentation was ascertained from the Danish Medical Birth Register, and we calculated mean differences in the BPP score according to maternal labor augmentation. We repeated our analyses in a sub-sample of siblings to control for unmeasured familial confounding.

RESULTS

Maternal labor augmentation was not associated with any noticeable decline in cognitive ability. However, the difference in the mean BPP score for exposure to maternal labor augmentation varied according to maternal parity, as the mean difference in BPP scores increased with increasing parity, in nulliparous: mean difference=-0.14 (95% CI=-0.23 to -0.04); in maternal parity 4+: mean difference=-1.21 (95% CI=-2.905 to -0.37). The sibling analysis showed little influence of shared familial factors on the association.

CONCLUSION

The mean BPP was slightly lower among labor augmented compared to nonaugmented and with an increasing difference with increasing parity. However, the differences were small and could not be considered of any clinical relevance. Furthermore, the sibling analyses suggested little confounding by familial factors.

Comparable risk of childhood asthma after vaginal delivery and emergency caesarean section

INTRODUCTION

Caesarean section is thought to be a risk factor for childhood asthma, but this association may be caused by confounding from, for instance, familial factors. To address this problem, we used twin pairs to assess the risk of childhood asthma after emergency caesarean section.

METHODS

The study was a register-based nation-wide matched cohort study using twin pairs to minimise residual confounding. Included were twin pairs in which the first twin was delivered vaginally and the second by emergency caesarean section during the study period from January 1997 through December 2012.

RESULTS

In total, 464 twin pairs (928 twins) were included. In 30 pairs, the first twin (vaginal delivery) was diagnosed with asthma, but the second twin (emergency caesarean section) was not. In 20 pairs, the second twin (emergency caesarean section) was diagnosed with asthma, but the first twin (vaginal delivery) was not. In 11 pairs, both twins developed asthma. In the unadjusted analysis, emergency caesarean section did not affect the risk of asthma (odds ratio = 0.67 (95% confidence interval: 0.38-1.17); p = 0.16). After adjusting for birth weight, gender, umbilical cord pH, Apgar score at 5 min. and neonatal respiratory morbidity, the risk of childhood asthma following emergency caesarean section remained unchanged.

CONCLUSION

Emergency caesarean section was not associated with childhood asthma.

FUNDING

none.

TRIAL REGISTRATION

not relevant.