How to define coronary heart disease in register-based follow-up studies: experience from the Helsinki Heart Study

Low-Density Lipoprotein Cholesterol and Mortality in Patients With Intracerebral Hemorrhage in Taiwan

Objective: Lower serum low-density lipoprotein cholesterol (LDL-C) levels are associated with increased intracerebral hemorrhage (ICH) risk. However, reverse causality and residual confounding has not attracted public attention. Therefore, we assessed whether people with LDL-C have increased risk of mortality adjusting for potential confounders using two large Taiwan cohorts.

Methods: The Mei-Jhao (MJ) cohort has 414,372 adults participating in a medical screening program with 378 ICH deaths within 15 years of follow-up (1994–2008). Cox proportional hazards regressions estimated hazard death ratios according to LDL-C levels. We identified 4,606 ICH patients from the Taiwan Stroke Registry (TSR) and analyzed the impact of LDL-C on 3-month mortality.

Results: Low cholesterol (LDL-C <100 mg/dL), found in 1/4 of the MJ cohort, was highly prevalent (36%) among young adults (age 20–39). There was a graded relationship between cholesterol and mortality for ICH [Hazard ratio, 1.56; 95% confidence interval (CI), 1.13–2.16]. Compared with patients with an LDL-C of 110–129 mg/dL in TSR, the risk for mortality was 1.84 (95% CI, 1.28–2.63) with an LDL-C of <100 mg/dL.

Conclusion: Lower serum LDL-C level independently predicts higher mortality after acute ICH. While its causative role may vary, low cholesterol may pose potential harms in Taiwan.

Elevated Monocytic Interleukin-8 Expression under Intermittent Hypoxia Condition and in Obstructive Sleep Apnea Patients

Obstructive sleep apnea (OSA) is a disease with great cardiovascular risk. Interleukin-8 (IL-8), an important chemokine for monocyte chemotactic migration, was studied under intermittent hypoxia condition and in OSA patients. Monocytic THP-1 cells were used to investigate the effect of intermittent hypoxia on the regulation of IL-8 by an intermittent hypoxic culture system. The secreted protein and mRNA levels were studied by means of enzyme-linked immunosorbent assay and RT/real-time PCR. The chemotactic migration of monocytes toward a conditioned medium containing IL-8 was performed by means of the transwell filter migration assay. Peripheral venous blood was collected from 31 adult OSA patients and RNA was extracted from the monocytes for the analysis of IL-8 expression. The result revealed that intermittent hypoxia enhanced the monocytic THP-1 cells to actively express IL-8 at both the secreted protein and mRNA levels, which subsequently increased the migration ability of monocytes toward IL-8. The ERK, PI3K and PKC pathways were demonstrated to contribute to the activation of IL-8 expression by intermittent hypoxia. In addition, increased monocytic IL-8 expression was found in OSA patients, with disease severity dependence and diurnal changes. This study concluded the monocytic IL-8 gene expression can be activated by intermittent hypoxia and increased in OSA patients.

Validity of Acute Cardiovascular Outcome Diagnoses Recorded in European Electronic Health Records: A Systematic Review

BACKGROUND

Electronic health records are widely used in cardiovascular disease research. We appraised the validity of stroke, acute coronary syndrome and heart failure diagnoses in studies conducted using European electronic health records.

METHODS

Using a prespecified strategy, we systematically searched seven databases from dates of inception to April 2019. Two reviewers independently completed study selection, followed by partial parallel data extraction and risk of bias assessment. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value estimates were narratively synthesized and heterogeneity between sensitivity and PPV estimates were assessed using I2.

RESULTS

We identified 81 studies, of which 20 validated heart failure diagnoses, 31 validated acute coronary syndrome diagnoses with 29 specifically recording estimates for myocardial infarction, and 41 validated stroke diagnoses. Few studies reported specificity or negative predictive value estimates. Sensitivity was ≤66% in all but one heart failure study, ≥80% for 91% of myocardial infarction studies, and ≥70% for 73% of stroke studies. PPV was ≥80% in 74% of heart failure, 88% of myocardial infarction, and 70% of stroke studies. PPV by stroke subtype was variable, at ≥80% for 80% of ischaemic stroke but only 44% of haemorrhagic stroke. There was considerable heterogeneity (I2 >75%) between sensitivity and PPV estimates for all diagnoses.

CONCLUSION

Overall, European electronic health record stroke, acute coronary syndrome and heart failure diagnoses are accurate for use in research, although validity estimates for heart failure and individual stroke subtypes were lower. Where possible, researchers should validate data before use or carefully interpret the results of previous validation studies for their own study purposes.

Monocytic C-C chemokine receptor 5 expression increases in in vitro intermittent hypoxia condition and in severe obstructive sleep apnea patients

Purpose

Obstructive sleep apnea (OSA) patients have higher risk of cardiovascular disease. C-C chemokine receptor 5 (CCR5), as an important receptor for monocyte recruitment and the initiation of atherosclerosis, was studied under intermittent hypoxia and in OSA patients.

Methods

The expression and function of CCR5 regulated by intermittent hypoxia in monocytic THP-1 cells were investigated in an in vitro intermittent hypoxia culture system. The expression levels of protein and mRNA were analyzed by western blot and RT/real-time PCR analysis. Cell adhesion assay and transwell filter migration assay were carried out to investigate the adhesion and chemotaxis of monocytes. In addition, the mRNA expression of CCR5 in monocytes isolated from peripheral blood of 72 adults was analyzed.

Results

Intermittent hypoxia upregulated the expression of CCR5 in THP-1 cells and enhanced the adhesion and chemotaxis of monocytes to vascular endothelial cells mediated by RANTES. The CCR5 expression induced by intermittent hypoxia was inhibited by inhibitor for p42/44 MAPK. Besides, the expression of CCR5 in monocytes increased along the AHI value especially in severe OSA patients that was statistically significant compared with mild and moderate OSA groups.

Conclusions

This study demonstrated the increased monocytic CCR5 gene expression in patients with severe OSA. Intermittent hypoxia, the characteristic of OSA, induced monocytic CCR5 gene expression and the enhanced RANTES-mediated chemotaxis and adhesion through p42/44 MAPK signal pathways.

Appropriateness of ICD-coded Diagnostic Inpatient Hospital Discharge Data for Medical Practice Assessment

Objectives: We performed a systematic review to investigate the quality of diagnostic hospital discharge data (DHDD) in order to gain insight in the usefulness of these data for medical practice assessment. We investigated the methods used to evaluate data quality, factors that determine data quality and its consequences for medical practice assessment.

Methods: We selected studies in which both completeness (or sensitivity: SENS) and correctness (or positive predictive value: PPV) were measured. We used the random-effects model to calculate mean SENS and PPV and to explore the effect of a number of covariates.

Results: The 101 included studies were very heterogeneous. We distinguished six typical study designs. We found a mean SENS of 0.67 (95%CI: 0.62– 0.73) and PPV of 0.76 (95%CI: 0.73– 0.79); SENS was significantly lower for comorbidity and complication studies than for some single disease studies. PPV was significantly higher for Scandinavian countries than for other countries. Recoding compared to re-abstracting of the medical record as a gold standard gave a significantly lower PPV. Diagnostic data were considered appropriate by the authors of the studies for quality of care purposes when both SENS and PPV were at least 0.85. Only 13% of the studies fulfilled this criterion.

Conclusions: Variability in quality of care between settings can easily be overshadowed by variability in data quality. However, the use of DHDD by physicians to evaluate their own medical practice may be useful. But only if physicians are willing to critically interpret the meaning of the information for their medical practice assessment.

Long-term outcome of medically treated epilepsy

PURPOSE

To review the long-term outcome of epilepsy in population-based studies.

METHOD

Analysis of population-based studies.

RESULTS

About two of three patients with new-onset epilepsy will, in the long run, enter five-year terminal remission. Chances for remission are best for those with idiopathic or cryptogenic epilepsy. It is unclear whether the seizure outcome has improved over the last several decades. Social outcome, however, may have become better because of the improved level of knowledge on and public attitudes toward people with epilepsy, and possibly fewer prejudices at home, daycare, school, military and labor market.

CONCLUSION

While we still do not have a cure for epilepsy for all patients, relief of the medical and social consequences is available for many and hope is on the horizon for people with epilepsy.

Epidemiology and long-term Turku outcome of childhood-onset epilepsy and mortality. Personal experiences. Part I

Introduction.Epidemiological studies on epilepsy were long based, with few exceptions, on hospital and institution patients with a subsequent bias toward more difficult cases and the reported prevalence and incidence rates were often obviously too low. Few data are available on the temporal changes in the incidence of epilepsy.

Aim.To study the prevalence and incidence in an unselected child population including all the children living either in the society or in the institution, temporal changes in the incidence and mortality through five decades.

Methods.The most important personal data were reviewed and compared with the relevant data of other investigators.

Results and discussion.The prevalence of epilepsy in our study was 3.2/1000, quite obviously true for the contemporary methodology and well comparable with 3.4–4.2/1000 of other relevant studies published about two decades later and using a more advanced methodology. Similarly, the incidence of 35/100 000, ascertained in two Finnish studies, was comparable with the relevant contemporary literature data. Another study of ours shows that, probably associated with the people “coming from the shadows” and an improved diagnostic methodology, the incidence of childhood epilepsy has increased and is now 60–70/100 000. However, the incidence of childhood epilepsy shows an obvious decreasing trend in the first two decades of the 2000s.

Conclusions.The incidence of childhood epilepsy, in all probability true for the contemporary methodology, was lower than it is now, but it now again shows a decreasing trend.

Quality of the Finnish Hospital Discharge Register: a systematic review

AIMS

The Finnish Hospital Discharge Register (FHDR) is one of the oldest individual level hospital discharge registers and has been intensively used for research purposes. The aim of this study was to gather information concerning the quality of FHDR into one place in terms of a systematic review of validation studies that compare data to external information.

METHODS

Several reference databases were searched for validity articles published until January 2012. For each included study, focus of validation, register years examined, number of compared observations, external source(s) of data, summary of validation results, and conclusions concerning the validity of FHDR were extracted.

RESULTS

In total, 32 different studies comparing FHDR data to external information were identified. Most of the studies examined validity in the case of vascular disease, mental disorders or injuries. More than 95% of discharges could be identified from the register. Positive predictive value (PPV) for common diagnoses was between 75 and 99%.

CONCLUSIONS

Completeness and accuracy in the register seem to vary from satisfactory to very good in the register as long as the recognised limitations are taking into account. Poor recording of subsidiary diagnoses and secondary operations and other rarely used items are the most obvious limitations in validity, but do not compromise the value of data in FHDR in being used in studies that are not feasible to conduct otherwise.

Joint effect of self-reported sleep problems and three components of the metabolic syndrome on risk of coronary heart disease

OBJECTIVE

This study explored the joint effect of two epidemics, sleep problems and metabolic syndrome (MetS), on the risk of coronary heart disease (CHD).

METHODS

The study group is part of the Finnish middle-aged men who participated in the first screening for the Helsinki Heart Study (HHS) in 1981-1982. At that time, three components of MetS were measured: body mass index, HDL cholesterol, and blood pressure. Later, in 1986-1988, they were given a psychosocial questionnaire including items on sleep problems. Of the respondents, 2753 formed our study group and were followed up using population-based registers until 1995. The relative risks (RR) of CHD were estimated using Cox's regression models.

RESULTS

When several sleep problems were present simultaneously, some increased CHD risk was observed. However, when considered jointly with MetS, insomnia or daytime fatigue approximately doubled the CHD risk and the presence of insufficient sleep more than tripled the risk. Among those who had MetS only, the RR was 2.55, and among those with both insufficient sleep and MetS the RR was 9.36 (95% confidence interval: 4.60-19.04; P for interaction 0.09) when compared to those with no insufficient sleep and no components of MetS.

CONCLUSION

The interaction occurred when all three measured MetS components were present, suggesting that co-occurrence of these two epidemics may predict growing public health problems.

Temporal changes in the incidence of epilepsy in Finland: nationwide study

PURPOSE

To examine possible changes over time in the incidence of epilepsy in different age groups.

METHODS

Based on the nationwide full-refundable antiepileptic drug register and population register, incidence of newly diagnosed epilepsy was measured by granted full-refundable antiepileptic drugs for epilepsy.

RESULTS

The incidence was throughout all age groups higher in men than in women. The incidence in the total population had significantly declined in 1986-2002, from 71.6/100,000 to 52.9/100,000. The incidence significantly decreased in children (0.77; 0.71-0.84, p<0.0001) and adults (0.83; 0.77-0.89, p<0.0001) but increased in the elderly (1.18; 1.10-1.26, p<0.0001). The increased incidence in the elderly over the time period was primarily seen in women.

CONCLUSION

The incidence of epilepsy has significantly declined in both children and adults with a concurrent increase in the incidence among the elderly. Further studies are needed to elucidate the precise cause of these temporal changes.

The triad of shift work, occupational noise, and physical workload and risk of coronary heart disease

BACKGROUND

Shift work, noise, and physical workload are very common occupational exposures and they tend to cluster in the same groups of workers.

OBJECTIVES

To study the short and long term effects of these exposures on risk of coronary heart disease (CHD) and to estimate the joint effects of these factors.

METHODS

The study population in this prospective 13 year follow up study of 1804 middle aged industrially employed men was collected at the first screening for the Helsinki Heart Study. The CHD end points (ICD-9 codes 410-414 and ICD-10 codes I20-I25) were obtained from official Finnish registers. The Finnish job-exposure matrix FINJEM provided information on occupational exposures. Relative risks (RR) of CHD for the exposures were estimated using Cox's proportional hazard models adjusting for classical risk factors of CHD.

RESULTS

The RR in the five year follow up for continuous noise combined with impulse noise was 1.28; for shift work it was 1.59, and for physical workload 1.18, while in the 13 year follow up the RRs were 1.58, 1.34, and 1.31, respectively. When adjusted for white-collar/blue-collar status the RRs decreased markedly. The RR in the 13 year follow up for those exposed to two risk factors was close to 1.7 and for those exposed to all three, 1.87.

CONCLUSION

Shift work and continuous noise entailed an excess risk for CHD in the shortest follow up with only a few retired workers but a decreasing risk during the longer follow up. For physical workload and impulse noise the trend was opposite: the CHD risk was increasing with increasing follow up time despite increasing numbers of retired workers.

The feasibility of routine mortality and morbidity register data linkage to study the occurrence of acute coronary heart disease events in Finland. The Finnish Cardiovascular Diseases Registers (CVDR) Project

Validated population-based data on the occurrence of coronary heart disease in Finland have previously been obtained from myocardial infarction (MI) registers. Such registers cannot, however, cover large areas. Therefore, the Finnish Cardiovascular Diseases Registers (CVDR) Project was set up to obtain data for the whole of Finland. The CVDR Project is based on routine mortality and morbidity data linkage. We report here the overall approach used in the project, the results of the feasibility study and the first main results. In Finland, data on all hospitalizations are registered in the nationwide Hospital Discharge Register. Also, data on all deaths are collected in the nationwide Causes of Death Register. The unique personal identification number assigned to all persons residing in Finland was used for data linkage. Data have been validated using the FINMONICA MI registers. Sensitivity analyses showed that the data were robust and consistent between different geographical areas. Coronary heart disease (CHD) mortality as well as the incidence and event rates showed the same very clear geographical pattern, dividing Finland to a southwest area with a lower occurrence and a northeast area with nearly twice higher occurrence. Case fatality did not differ much between the areas and did not follow this Southwest-Northeast division. The differences between northeast and southwest Finland may be related to differences in risk factor levels but also to socioeconomic and genetic differences. The CVDR Project data will be instrumental in further research addressing these issues.

Natural selection to sports, later physical activity habits, and coronary heart disease

OBJECTIVES

To investigate the associations between natural selection to sports at a young age, continuity of physical activity, and occurrence of coronary heart disease.

DESIGN

Prospective cohort study.

SETTING

Finland.

PARTICIPANTS

Former top level male athletes participating at a young age (1920-1965) in different types of sport (endurance (n = 166), power speed (n = 235), "other" (n = 834)) and controls healthy at the age of 20 years (n = 743).

MAIN OUTCOME MEASURES

Data on the occurrence of coronary heart disease were obtained from death certificates, three nationwide registers, and questionnaire studies in 1985 and 1995, and data on later physical activity were obtained from the questionnaires.

RESULTS

In 1985 all groups of former athletes were more physically active than controls (p<0.001). Despite similar total volumes of physical activity, compared with power speed athletes, former endurance athletes participated more often in vigorous activity (p = 0.006) and had less coronary heart disease (adjusted odds ratio 0.34, 95% confidence interval 0.17 to 0.73; p = 0.004). In 1985 and 1995, both endurance and other athletes had less coronary heart disease than controls. From 1986 to 1995, the incidence of new coronary heart disease was lower among those who participated in vigorous physical activity in 1985.

CONCLUSIONS

Both a previous aptitude for endurance athletic events and continuity of vigorous physical activity seem to be associated with protection against coronary heart disease, but an aptitude for power speed events does not give protection against coronary heart disease.

Physical activity and other risk factors in male twin-pairs discordant for coronary heart disease

BACKGROUND

Twin-pairs discordant for coronary heart disease (CHD) can be used to examine the possible contribution of genetic and other familial factors to the relationship between CHD risk factors, in particular physical inactivity at leisure, and CHD.

METHODS AND RESULTS

In 1975 at baseline, 8205 men aged 25-69 years of the Finnish Twin Cohort without overt CHD responded to a questionnaire. The outcome measures were hospitalization for CHD or death from CHD before age 70 between 1977 to 1995 based on reliable nationwide registries. Among all men, the age-adjusted relative risk of CHD was 0.52 (95% confidence interval (CI) 0.39, 0.71) in men participating in conditioning exercise compared to sedentary men, based on their questionnaire responses. The age, and covariate (body-mass index, smoking, hypertension, diabetes) adjusted-relative risk was 0.68 (CI 0.50, 0.92). Among the twin-pairs discordant for CHD during follow-up (N=311), the odds ratio (OR) of having CHD was 0.54 (CI 0. 27, 1.09) for conditioning exercisers compared to sedentary men. The point estimates from discordant pairs analyses were of the same magnitude as obtained from the analyses of individuals, though statistically not significant due to smaller samples. In contrast, smoking (OR 3.21) and diabetes (OR 10.0) at baseline were also significant predictors of CHD.

CONCLUSIONS

By studying twins we were able to examine genetic and other familial selection bias and found further supporting evidence that leisure conditioning physical exercise compared to sedentariness helps prevent CHD in men, but smoking was a stronger risk factor.

Future hospital care in a population-based series of twin pairs discordant for physical activity behavior

OBJECTIVES

This study investigated the association between physical activity behavior and morbidity, taking into account genetic selection.

METHODS

Hospitalizations were followed from the beginning of 1977 to the end of 1986 in 710 same-sex healthy twin pairs discordant for leisure-time physical activity and in 151 pairs discordant for all physical activity at base-line in 1975.

RESULTS

During the follow-up, among twin pairs discordant for leisure activity, the active member spent, on average, 43% fewer days in the hospital than the inactive member; the corresponding percentage was 55% among pairs discordant for all activity.

CONCLUSIONS

Physically inactive behavior is associated with increased need for hospital treatments, even after genetic and other confounding factors are taken into account.

The sense of coherence, occupation and the risk of coronary heart disease in the Helsinki Heart Study

The risk of coronary heart disease (CHD) was studied in 4405 Finnish middle-aged working men in different occupations according to their sense of coherence (SOC). The study design was prospective and the follow-up time was eight years. Clinical findings such as total cholesterol, systolic blood pressure and body-mass index showed differences when comparing blue and white collar workers. Lifestyle factors such as smoking also differed, but leisure time physical activity depended on SOC. In the white collar work environment the low SOC tertile had a high CHD incidence of 20.1 per 1000 person-years; the incidences in the medium and high SOC tertiles were 10.9 and 12.3, respectively. A similar effect was not observed in the blue collar work environment. There, contrary to theoretical expectations, the low SOC tertile had the lowest incidence of CHD. The difference in the CHD incidence pattern depended on the blue and white collar dichotomy and not on the branch (state agencies vs. industry). The SOC had a salutogenic effect among white collar workers, but failed to have any consequent effect on the health of blue collar workers. Further study is needed to look at the psychosocial factors among blue collar workers.