Smoking timing, genetic susceptibility and the risk of incident type 2 diabetes: A cohort study from the UK Biobank

AIM

To prospectively assess the association of smoking timing with the risk of type 2 diabetes (T2D) and examine whether smoking amount or genetic susceptibility might modify the relationship.

MATERIALS AND METHODS

A total of 294 815 participants without diabetes from the UK Biobank, including non-smokers and smokers with data on the time from waking to first cigarette, were included. Cox proportional hazards models were used to evaluate the association between smoking timing and the risk of incident T2D.

RESULTS

During a median follow-up time of 12 years, a total of 9937 incident cases of T2D were documented. Compared with non-smokers, a shorter time from waking to first cigarette was significantly associated with a higher risk of incident T2D (P for trend < .001). In the fully adjusted model, the hazard ratios (HRs) (95% confidence interval) associated with smoking timing were 1.46 (1.17-1.81) for more than 2 hours, 1.51 (1.21-1.87) for 1-2 hours, 1.58 (1.34-1.85) for 30-60 minutes, 1.86 (1.57-2.21) for 5-15 minutes and 2.01 (1.60-2.54) for less than 5 minutes. We found that even among those who reported being light smokers, those with the shortest time from waking to first cigarette had a 105% higher risk of T2D with an HR of 2.05 (1.52-2.76), which was comparable with heavy smokers. The genetic risk score for T2D did not modify this association (P-interaction = .51).

CONCLUSIONS

Our findings indicate that shorter time from waking to first cigarette is significantly associated with a higher risk of incident T2D.

Degree of joint risk factor control and hazard of mortality in diabetes patients: a matched cohort study in UK Biobank

BACKGROUND

Diabetes patients are at higher risk for mortality than the general population; however, little is known about whether the excess mortality risk associated with diabetes could be mitigated or nullified via controlling for risk factors.

METHODS

We included 18,535 diabetes patients and 91,745 matched individuals without diabetes without baseline cancer or cardiovascular disease (CVD), followed up from 2006 to 2021. The main exposure was the number of optimized risk factors including glycated hemoglobin < 53 mmol/mole, systolic blood pressure < 140 mmHg and diastolic blood pressure < 90 mmHg, no albuminuria, non-current smoking and low-density lipoprotein cholesterol (LDL-C) < 2.5 mmol/L. We used Cox proportional hazards models to explore the association of the degree of risk factor control with all-cause mortality, cancer mortality, CVD mortality and other mortality.

RESULTS

Each additional risk factor control was associated with a 16, 10, 21 and 15% lower risk of all-cause mortality, cancer mortality, CVD mortality and other mortality, respectively. Optimal risk factors control (controlling 5 risk factors) was associated with a 50% (HR 0.50, 95% CI 0.41-0.62), 74% (HR 0.26, 95% CI 0.16-0.43) and 38% (HR 0.62, 95% CI 0.44-0.87) lower risk of all-cause mortality, CVD mortality and other mortality, respectively. Diabetes patients with 4, 3 and 5 or more controlled risk factors, respectively, showed no excess risk of all-cause mortality, cancer mortality and CVD mortality compared to matched non-diabetes patients.

CONCLUSIONS

The results from this study indicate that optimal risk factor control may eliminate diabetes-related excess risk of all-cause mortality, CVD mortality and other mortality.

Degree of Risk Factor Control and Incident Cardiovascular Diseases in Patients With Hypertension

OBJECTIVE

To investigate whether joint risk factor control could reduce the excess risk of cardiovascular disease (CVD) in patients with hypertension.

PATIENTS AND METHODS

A total of 75,293 patients with diagnosed hypertension from the UK Biobank study were included, matched with 256,619 nonhypertensive controls, and followed up until May 31, 2021. Seven risk factors were measured to define joint risk factor control, including blood pressure, body mass index, low-density lipoprotein cholesterol, hemoglobin A1c, albuminuria, smoking, and physical activity.

RESULTS

Among hypertensive patients, 14% to 24% lower risks of CVD outcomes were associated with each additional risk factor control. In the Cox proportional hazards models, adjusted hazard ratios for patients with 6 or more risk factor controls compared with patients having 2 or less risk factor controls were 0.49 (95% CI, 0.45 to 0.55) for CVD, 0.51 (95% CI, 0.45 to 0.57) for coronary heart disease, 0.48 (95% CI, 0.38 to 0.60) for stroke, and 0.34 (95% CI, 0.26 to 0.44) for CVD mortality. The excess risks of CVD outcomes in patients with hypertension were diminished to nonsignificant or even lower compared with controls if achieving 6 or more risk factor controls. Men experienced stronger protective associations of joint risk factor control on risks of CVD than women (P<.001 for interaction).

CONCLUSION

The joint risk factor control is associated with lower risks of CVD, and a high degree of risk factor control may considerably attenuate the excess risk of CVD among patients with hypertension.

Self-Reported Frequency of Adding Salt to Food and Risk of Incident Chronic Kidney Disease

Importance

The self-reported frequency of adding salt to foods could reflect a person's long-term salt taste preference, and salt intake has been associated with increased risk of cardiovascular diseases (CVD). Whether self-reported adding of salt to foods is associated with increased risk of chronic kidney disease (CKD) remains unknown.

Objective

To prospectively examine the association of self-reported frequency of adding salt to foods with incident CKD risk in a general population of adults.

Design, Setting, and Participants

This population-based cohort study evaluated UK Biobank participants aged 37 to 73 years who were free of CKD at baseline. Participants were enrolled from 2006 to 2010 and prospectively followed up for disease diagnosis. Data were analyzed from October 2022 to April 2023.

Exposure

Self-reported frequency of adding salt to foods, categorized into never or rarely, sometimes, usually, and always.

Main Outcome and Measure

Incident CKD cases were defined by diagnostic codes. Hazard ratios (HRs) and 95% CIs were calculated by using Cox proportional hazards models. Models were adjusted for several potential confounders including age, sex, race and ethnicity, Townsend Deprivation Index, estimated glomerular filtration rate (eGFR), body mass index, (BMI), smoking status, alcohol drinking status, regular physical activity, high cholesterol, diabetes, CVD, hypertension, infectious disease, immune disease, and nephrotoxic drugs use at baseline.

Results

Within a cohort of 465 288 individuals (mean [SD] age 56.32 [8.08] years; 255 102 female participants [54.83%]; 210 186 male participants [45.17%]), participants with higher self-reported frequency of adding salt to foods were more likely to have a higher BMI, higher Townsend Deprivation Index score, and diminished baseline eGFR compared with those who reported a lower frequency of adding salt to foods. Participants who added salt to their foods were also more likely than those who did not add salt to their foods to be current smokers and have diabetes or CVD at baseline. During a median (IQR) follow-up of 11.8 (1.4) years, 22 031 incident events of CKD were documented. Higher self-reported frequency of adding salt to foods was significantly associated with a higher CKD risk after adjustment for covariates. Compared with those who reported never or rarely adding salt to foods, those who reported sometimes adding salt to food (adjusted HR [aHR], 1.04; 95% CI, 1.00-1.07), those who reported usually adding salt to food (aHR, 1.07; 95% CI, 1.02-1.11), and those who reported always adding salt to food (aHR, 1.11; 95% CI, 1.05-1.18) had an increased risk of CKD (P for trend < .001). In addition, eGFR, BMI, and physical activity significantly modified the associations, which were more pronounced among participants with a higher eGFR, lower BMI, or lower level of physical activity.

Conclusions and Relevance

In this cohort study of 465 288 individuals, a higher self-reported frequency of adding salt to foods was associated with a higher risk of CKD in the general population. These findings suggest that reducing the frequency of adding salt to foods at the table might be a valuable strategy to lower CKD risk in the general population.

DNA Methylation at ABCG1 and Long-term Changes in Adiposity and Fat Distribution in Response to Dietary Interventions: The POUNDS Lost Trial

OBJECTIVE

To examine whether participants with different levels of diabetes-related DNA methylation at ABCG1 might respond differently to dietary weight loss interventions with long-term changes in adiposity and body fat distribution.

RESEARCH DESIGN AND METHODS

The current study included overweight/obese participants from the POUNDS Lost trial. Blood levels of regional DNA methylation at ABCG1 were profiled by high-resolution methylC-capture sequencing at baseline among 673 participants, of whom 598 were followed up at 6 months and 543 at 2 years. Two-year changes in adiposity and computed tomography-measured body fat distribution were calculated.

RESULTS

Regional DNA methylation at ABCG1 showed significantly different associations with long-term changes in body weight and waist circumference at 6 months and 2 years in dietary interventions varying in protein intake (interaction P < 0.05 for all). Among participants assigned to an average-protein (15%) diet, lower baseline regional DNA methylation at ABCG1 was associated with greater reductions in body weight and waist circumference at 6 months and 2 years, whereas opposite associations were found among those assigned to a high-protein (25%) diet. Similar interaction patterns were also observed for body fat distribution, including visceral adipose tissue, subcutaneous adipose tissue, deep subcutaneous adipose tissue, and total adipose tissue at 6 months and 2 years (interaction P < 0.05 for all).

CONCLUSIONS

Baseline DNA methylation at ABCG1 interacted with dietary protein intake on long-term decreases in adiposity and body fat distribution. Participants with lower methylation at ABCG1 benefitted more in long-term reductions in body weight, waist circumference, and body fat distribution when consuming an average-protein diet.

Dietary Sodium Intake and Risk of Incident Type 2 Diabetes

OBJECTIVE

To fill the knowledge gap of the relation between long-term dietary sodium intake and type 2 diabetes (T2D), we evaluate the association between the frequency of adding salt to foods, a surrogate marker for evaluating the long-term sodium intake, and incident T2D risk.

METHODS

A total of 402,982 participants from UK Biobank (March 13, 2006 - October 10, 2010) who were free of diabetes, chronic kidney disease, cancer, or cardiovascular disease at baseline, and had completed information on adding salt were analyzed in this study.

RESULTS

During a median of 11.9 years of follow-up, 13,120 incident cases of T2D were documented. Compared with participants who "never/rarely" added salt to foods, the adjusted HRs were 1.11 (95% CI, 1.06 to 1.15), 1.18 (95% CI, 1.12 to 1.24), and 1.28 (95% CI, 1.20 to 1.37) across the groups of "sometimes," "usually," and "always," respectively (P-trend<.001). We did not find significant interactions between the frequency of adding salt to foods and baseline hypertension status and other covariates on the risk of incident T2D. The observed positive association was partly mediated by body mass index, waist to hip ratio, and C-reactive protein, with a significant mediation effect of 33.8%, 39.9%, and 8.6%, respectively. The significant mediation effect of body mass index was largely driven by the body fat mass rather than the body fat-free mass.

CONCLUSION

Our findings for the first time indicate that higher frequency of adding salt to foods, a surrogate marker for a person's long-term salt taste preference and intake, is associated with a higher T2D risk.

DNA Methylation Near CPT1A and Changes in Triglyceride-rich Lipoproteins in Response to Weight-loss Diet Interventions

CONTEXT

Carnitine palmitoyltransferase-1A, encoded by the CPT1A gene, plays a key role in the oxidation of long-chain fatty acids in the mitochondria and may be important in triglyceride metabolism. Previous work has shown that high fat intake was negatively associated with CPT1A methylation and positively associated with CPT1A expression.

OBJECTIVE

We aim to investigate the association of DNA methylation (DNAm) at the CPT1A gene with reductions in triglycerides and triglyceride-rich lipoproteins (TRLs) in response to weight-loss diet interventions.

METHODS

The current study included 538 White participants, who were randomly assigned to 1 of 4 diets varying in macronutrient components. We defined the regional DNAm at CPT1A as the average methylation level over CpGs within 500 bp of the 3 triglyceride-related DNAm sites.

RESULTS

Dietary fat intake significantly modified the association between baseline DNAm at CPT1A and 2-year changes in total plasma triglycerides, independent of concurrent weight loss. Among participants assigned to a low-fat diet, a higher regional DNAm level at CPT1A was associated with a greater reduction in total plasma triglycerides at 2 years (P = .01), compared with those assigned to a high-fat diet (P = .64) (P interaction = .018). Further investigation on lipids and apolipoproteins in very low-density lipoprotein (VLDL) revealed similar interaction patterns for 2-year changes in VLDL-triglycerides, VLDL-cholesterol, and VLDL-apolipoprotein B (P interaction = .009, .002, and .016, respectively), but not for VLDL-apoC-III (P interaction = .36).

CONCLUSION

Participants with a higher regional DNAm level at CPT1A benefit more in long-term improvement in triglycerides, particularly in the TRLs and related apolipoproteins when consuming a low-fat weight-loss diet.

DNA Methylation of Birthweight-Blood Pressure Genes and Changes of Blood Pressure in Response to Weight-Loss Diets in the POUNDS Lost Trial

BACKGROUND

DNA methylation (DNAm) may play a critical role in bridging prenatal adverse events and cardiometabolic disorders including hypertension in later life.

METHODS

We included 672 adult participants with overweight or obesity, who participated in a 2-year randomized weight-loss dietary intervention study. We defined the regional DNAm levels as the average methylation level of 5'-cytosine-phosphate-guanine-3' within 500 bp of LINC00319 (cg01820192), ATP2B1 (cg00508575), and LMNA (cg12593793), respectively. Generalized linear regression models were used to assess the association between the regional DNAm and 2-year blood pressure changes. Trajectory analysis was used to identify subgroups that shared a similar underlying trajectory of 2-year blood pressure changes.

RESULTS

The regional DNAm at LINC00319, showed significantly different associations with 2-year changes in systolic blood pressure and diastolic blood pressure among participants assigned to low- or high-fat diets (P for interaction<0.05 for all). In response to the low-fat diet, per SD higher regional DNAm at LINC00319 was associated with greater reductions in both 2-year changes in systolic blood pressure (β, -1.481; P=0.020) and diastolic blood pressure (β, -1.096; P=0.009). Three trajectories of changes in systolic blood pressure or diastolic blood pressure were identified, and participants with higher regional DNAm at LINC00319 were more likely to experience and maintain decreased systolic blood pressure and diastolic blood pressure (odds ratio of being in decrease-stable versus stable [95% CI], 1.542 [1.146-2.076] and 1.463 [1.125-1.902]).

CONCLUSIONS

Our findings suggest that DNAm could be a metabolic memory bridging early and later life, and an indicator of more benefits from eating a low-fat weight-loss diet.

[Establishment and validation of clinical prediction model for steroid-resistant nephrotic syndrome in children]

Objective: To identify the clinically relevant factors of steroid-resistant nephrotic syndrome (SSNS) in children and establish a predictive model followed by verifying its feasibility. Methods: A retrospective analysis was performed in a total of 111 children with nephrotic syndrome admitted to Children's Hospital of ShanXi from January 2016 to December 2021. The clinical data of general conditions, manifestations, laboratory tests, treatment, and prognosis were collected. According to the steroid response, patients were divided into SSNS and steroid resistant nephrotic syndrome (SRNS) group. Single factor Logistic regression analysis was used for comparison between the 2 groups, and variables with statistically significant differences were included in multivariate Logistic regression analysis. The multivariate Logistic regression analysis was used to identify the related variables of children with SRNS. The area under the receiver operating characteristic curve (ROC), the calibration curve and the clinical decision curve were used to evaluate its effectiveness of the variables. Results: Totally 111 children with nephrotic syndrome was composed of 66 boys and 45 girls, aged 3.2 (2.0, 6.6) years. There were 65 patients in the SSNS group and 46 in the SRNS group.Univariate Logistic regression analysis showed that the 6 variables, including erythrocyte sedimentation rate, 25-hydroxyvitamin D, suppressor T cells, D-dimer, fibrin degradation products, β2-microglobulin, had statistically significant differences between SSNS and SRNS groups (85 (52, 104) vs. 105 (85, 120) mm/1 h, 18 (12, 39) vs. 16 (12, 25) nmol/L, 0.23 (0.19, 0.27) vs. 0.25 (0.20, 0.31), 0.7 (0.6, 1.1) vs. 1.1 (0.9, 1.7) g/L, 3.1 (2.3, 4.1) vs. 3.3 (2.7, 5.8) g/L, 2.3 (1.9,2.8) vs. 3.0 (2.5, 3.7) g/L, χ²=3.73, -2.42, 2.24, 3.38, 2.24,3.93,all P<0.05), were included in the multivariate Logistic regression analysis. Finally, we found that 4 variables including erythrocyte sedimentation rate, suppressor T cells, D-dimer and β2-microglobulin (OR=1.02, 1.12, 25.61, 3.38, 95%CI 1.00-1.04, 1.03-1.22, 1.92-341.04, 1.65-6.94, all P<0.05) had significant correlation with SRNS. The optimal prediction model was selected. The ROC curve cut-off=0.38, with the sensitivity of 0.83, the specificity of 0.77 and area under curve of 0.87. The calibration curve showed that the predicted probability of SRNS group occurrence was in good agreement with the actual occurrence probability, χ²=9.12, P=0.426. The clinical decision curve showed good clinical applicability. The net benefit is up to 0.2. Make the nomogram. Conclusions: The prediction model based on the 4 identified risk factors including erythrocyte sedimentation rate, suppressor T cells, D-dimer and β2-microglobulin was suitable for the early diagnosis and prediction of SRNS in children. The prediction effect was promising in clinical application.

Abstract P157: Genetically Determine Gut Microbiome Abundance, Obese, and Incident Type 2 Diabetes

Introduction: Gut microbiota has been linked to the body’s adiposity and the development of type 2 diabetes (T2D). A recent genome-wide association study identified that genetic variants at the ABO locus (SNPs rs8176645 and rs550057) were associated with the abundance of gut microbiome (i.e., Bifidobacterium bifidum and Collinsella aerofaciens, respectively).

Hypothesis: We assessed the hypothesis that the genetically determined gut microbiome abundance was associated with incident T2D, and such association could be modified by obese status.

Methods: A total of 339,465 European ancestry participants who are initially free of T2D at baseline and have available information on genetic variants from the UK Biobank population were included in this study. The genetic risk score (GRS) was constructed by the risk alleles of the two genetic variants at the ABO locus. Cox proportional hazard models were used to estimate the associations between the genetic variants/GRS and incident T2D.

Results: During a median of 11.8 years of follow-up, 11,566 incident T2D were documented. We observed that the gut microbiome-related variants rs8176645 and rs550057 were both significantly associated with incident T2D after adjustment for sex, age, body mass index (BMI), Townsend deprivation index, smoking, drinking, regular physical activity, and diet score at baseline (hazard ratio [HR] per copy of risk allele A of rs8176645 1.05, 95% CI [1.02-1.09], P -value=0.001; HR per copy of risk allele T of rs550057 1.06, 95% CI [1.03-1.09], P -value<0.001; respectively). The GRS also showed a significant association with T2D incidence in the fully adjusted model (HR=1.03, 95% CI [1.01-1.05], P -value<0.001). In addition, we found that BMI significantly modified the associations between GRS and T2D, which were more pronounced in non-obese participants ( P -interaction=0.008).

Conclusion: Our findings indicate that the genetically determined gut microbiome abundance significantly predicts T2D risk, independent of traditional risk factors.

Abstract 65: DNA Methylation at ABCG1 and Long-Term Changes in Adiposity in Response to Diet Interventions: The POUNDS Lost Trial

Introduction: Epigenome-wide association studies identified that DNA methylation (DNAm) at the ABCG1 gene (cg06500161) was associated with obesity. However, little is known about whether DNAm at ABCG1 is associated with long-term changes in adiposity and body fat distribution in response to dietary weight-loss interventions.

Hypothesis: We hypothesized that participants with varying DNAm at ABCG1 might respond differently to dietary weight-loss interventions on long-term changes in adiposity and body fat distribution.

Methods: The current study included 673 participants with overweight/obesity, who were randomly assigned to 1 of 4 diets varying in macronutrient components. Blood DNAm level was profiled by a high-resolution methylC-capture sequencing at baseline. The regional DNAm at ABCG1 was defined as the average methylation level over CpGs within ± 250 bp of cg06500161. Two-year changes in adiposity and Computed Tomography (CT)-measured body fat distribution were calculated.

Results: We found that regional DNAm at ABCG1 significantly interacted with dietary protein intake on long-term changes in body weight and waist circumference (WC) at 6 months and 2 years (P-interaction<0.05 for all, Figure ). Among participants assigned to an average-protein (15%) diet, lower regional DNAm at ABCG1 was associated with greater reductions in body weight and WC at 6 months and 2 years, while opposite associations were found among those assigned to a high-protein (25%) diet. Similar interactions were also observed for body fat distribution, including visceral adipose tissue, subcutaneous adipose tissue, deep subcutaneous adipose tissue, and total adipose tissue at 6 months and 2 years (P-interaction<0.05 for all).

Conclusion: Our data indicate that DNAm at ABCG1 interacted with dietary protein intake on long-term changes in adiposity and body fat distribution. Participants with hypomethylation at ABCG1 benefited more in long-term improvement in adiposity and body fat distribution by consuming an average-protein diet.

Abstract P423: Adding Salt to Foods is Associated With the Risk of Incident Chronic Kidney Diseases

Introduction: We recently found the frequency of adding salt to foods could reflect a person’s long-term salt taste preference and intake and was related to the risk of cardiovascular diseases. Whether adding salt to foods is related to chronic kidney disease (CKD) remains unknown.

Hypothesis: We assessed the hypothesis that the frequency of adding salt to foods was associated with incident CKD risk in a general population of adults.

Methods: A total of 465,288 participants initially free of CKD at baseline from the UK Biobank cohort with completed information on adding salt were analyzed in this study. Incident CKD cases were identified by ICD-10 codes and OPCS-4 codes. Cox proportional hazard models were used to estimate the association between the frequency of adding salt to foods and incident CKD.

Results: During a median follow-up of 11.8 years, we documented 22,031 incident events of CKD. A higher frequency of adding salt to foods was significantly related to a higher CKD risk after adjustment for sex, age, race, body mass index (BMI), Townsend deprivation index, smoking, drinking, regular physical activity, high cholesterol, cardiovascular diseases (CVD), diabetes at baseline. Compared with the “never/rarely” group, the adjusted HRs (95% CI) of “sometimes”, “usually”, and “always” groups were 1.03 (0.99, 1.07), 1.07 (1.02, 1.11), 1.12 (1.06, 1.19), respectively ( P -trend<0.001). In addition, we found that estimated glomerular filtration rate (eGFR), BMI and physical activity significantly modified the associations, which were more pronounced in participants with higher level of eGFR, and lower level of BMI or physical activity (P-interaction=0.003, 0.004 and 0.02, respectively).

Conclusion: Our findings for the first time indicate that a higher frequency of adding salt to foods is associated with a higher CKD risk in the general population.

Abstract P119: Circulating microRNA-122 and Improvement in Cardiovascular Health in Response to Weight-Loss Diets: The Preventing Overweight Using Novel Dietary Strategies (Pounds Lost) Trial

Introduction: The microRNA-122 (miR-122) is widely involved in the post-transcriptional regulation of glucose and lipid metabolism, and cardiovascular system.

Hypothesis: We assessed the hypothesis that decrease in circulating miR-122-5p would be associated with the improvement in cardiovascular health (CVH) score and each component health metric in response to dietary weight-loss interventions.

Methods: Circulating miR-122-5p levels were measured at baseline and 6 months among 509 participants with overweight or obesity from the POUNDS LOST trial. We evaluated the CVH score using the newly updated algorithm -life’s essential 8 and calculated the composite score from the available biological health factors (body mass index [BMI], blood lipids, blood glucose, and blood pressure) across the 2-year intervention period.

Results: At baseline, lower levels of miR-122-5p were associated with higher CVH scores (P<0.001). Greater decreases in log-transformed miR-122-5p induced by calorie-restricted diets were significantly associated with greater improvement in overall CVH score (β[SE]= -2.98[0.7], P<0.001), non-HDL metric (β[SE]= -3.72[1.33], P=0.005) and BMI metric (β[SE]= -4.78[1.12], P<0.001) over 6 months. The trajectory of the composite CVH score over the 2-year intervention period differed significantly between the patterns of change in miR-122-5p ( P time*miR-122-5p =0.001). We also found a significant interaction between change in miR-122-5p and dietary fat intake on the 6-months change in CVH ( P = 0.025); a greater decrease in miR-122-5p showed a greater improvement in CVH at 6 months among participants assigned to a low-fat diet.

Conclusions: In conclusion, participants with decreased circulating miR-122-5p levels in response to dietary weight-loss interventions had significant improvement in CVH and achieved CVH benefits most strongly when consuming a low-fat diet.

Abstract P619: DNA Methylation at SREBF1 and Long-Term Changes in Body Composition: The POUNDS Lost Trial

Introduction: A previous epigenome-wide association study has causally linked DNA methylation (DNAm) at the SREBF1 gene (cg11024682) with obesity and lipids. However, little is known about whether DNAm at SREBF1 is associated with long-term changes in body adiposity and composition.

Hypothesis: We hypothesized that participants with different DNAm at SRBF1 might respond differently to dietary weight-loss interventions on changes in body adiposity and composition.

Methods: The current study included 314 individuals with overweight or obese, who participated in POUNDS Lost: a 2-year randomized dietary weight-loss trial. The blood DNAm level was profiled by methylC-capture sequencing at baseline. Regional DNAm at SREBF1 was calculated as the average methylation level over CpGs within ±250 bp of cg11024682. Body composition, including total fat mass (FM), percentage of FM (FM%), total fat-free mass (FFM), percentage of FFM (FFM%), and percentage of trunk fat (TF%) were measured by dual-energy X-ray absorptiometry (DEXA) at baseline, 6 months, and 2 years.

Results: Lower regional DNAm at SREBF1 was significantly associated with changes in body composition across 2 years ( Table ). At 6 months, per SD lower regional DNAm at SREBF1 was significantly associated with greater reductions in FM (β [SE] -0.23 [0.07], p=0.002), FM% (-0.30 [0.09], p<0.001), and TF% (-0.44 [0.13], p<0.001), and greater increases in FFM (0.18 [0.08], p=0.028) and FFM% (0.30 [0.09], p<0.001), regardless of dietary intervention groups and independent of concurrent weight loss. Such association remained at 2 years: FM (β [SE] -0.21 [0.10], p=0.045), FM% (-0.32 [0.11], p=0.004), TF% (-0.36 [0.16], p=0.026), FFM (0.22 [0.12], p=0.07) and FFM% (0.32 [0.11], p=0.004).

Conclusions: Overweight and obese individuals with a lower regional DNAm at SREBF1 achieved greater improvement in body composition across the 2-year intervention, independent of concurrent weight loss, suggesting DNAm at SREBF1 is predictive of individuals’ response to treatment.

Abstract 56: DNA Methylation of Birthweight-Blood Pressure Genes and Changes of Blood Pressures in Response to Weight-Loss Diets

Introduction: DNA methylation (DNAm) may play a critical role in bridging prenatal adverse events and cardiometabolic disorders including hypertension in later life.

Hypothesis: DNAm levels of genes related to both birthweight and blood pressure were associated with changes in blood pressures in response to dietary weight-loss interventions.

Methods: We included 672 adult participants with overweight or obesity, who participated in a 2-year randomized weight-loss dietary intervention study. Baseline blood DNAm levels were profiled by high-resolution methylC-capture sequencing. We defined the regional DNAm levels as the average methylation level within 500 bp of LINC00319 (cg01820192), ATP2B1 (cg00508575), and LMNA (cg12593793). Generalized linear regression models were used to assess the association between the regional DNAm and 2-year blood pressure changes. Trajectory analysis was used to identify subgroups that shared a similar underlying trajectory of 2-year blood pressure changes.

Results: We found that the regional DNAm at LINC00319, but not the other genes, showed different associations with 2-year changes in systolic blood pressure (SBP) and diastolic blood pressure (DBP) among participants assigned low- or high-fat diets (P for interaction < 0.05 for all, Figure ). In response to low-fat diet, per standard deviation higher regional DNAm at LINC00319 was associated with greater reductions in both 2-year changes in SBP (β: -1.481; standard error [SE]: 0.632; P = 0.020) and DBP (β: -1.096; SE: 0.413; P = 0.009). Three trajectories of changes in SBP and DBP were identified, and participants with higher baseline regional DNAm at LINC00319 were less likely to have stable or increased blood pressure levels.

Conclusions: Our findings indicate that higher regional DNAm level at LINC00319 was significantly associated with greater long-term reduction in blood pressure in response to a low-fat diet, suggesting people with higher regional DNAm levels benefited more from eating a low-fat weight-loss diet.

Abstract P338: Circulating microRNA-19 and Cardiovascular Risk Reduction in Response to Weight-Loss Diets: The Preventing Overweight Using Novel Dietary Strategies (Pounds Lost) Trial

Introduction: MicroRNA-19 (MiR-19) plays a critical role in cardiac development and cardiovascular disease (CVD).

Hypothesis: We assessed the hypothesis that change in circulating miR-19 would be associated with changes in 10-year atherosclerotic CVD (ASCVD) risk and individual cardiovascular risk factors in a dietary weight-loss intervention.

Methods: This study included 509 participants with overweight or obesity from the 2-year weight-loss diet intervention study (the POUNDS LOST trial) and with available data on circulating miR-19a/b-3p at baseline and 6 months. The primary outcome was the 6-month change in the ASCVD risk score, which estimates the 10-year probability of hard ASCVD events. Secondary outcomes were the change in each ASCVD component including blood pressure, lipid profiles, insulin resistance, glucose metabolism, and adiposity measures. Change in habitual physical activity and sleep disturbance were assessed from baseline to 6 months.

Results: Circulating miR-19a/b-3p levels significantly decreased during the initial 6-month dietary intervention period (P=0.008, 0.0004, respectively). We found that greater decreases in log-transformed miR-19a/b-3p were related to a greater reduction in ASCVD risk (β[SE]=0.35 [0.13], P=0.01 for miR-19a-3p; β[SE]=0.33 [0.13], P=0.01 for miR-19b-3p) over 6 months. Similar positive associations were observed for changes in diastolic blood pressure with miR-19a/b-3p. Moreover, we found that sleep disturbance was significantly associated with reductions in miR-19a/b-3p from baseline to 6 months (P trend <0.05). There were significant interactions between changes in miR-19a/b-3p and sleep disturbance for changes in ASCVD risk (P interaction<0.005). Participants with greater decreases in miR-19a/b-3p with no/slight amount of sleep disturbance had a greater reduction of ASCVD risk from baseline to 6 months than those with moderate/great amount of sleep disturbance. In addition, changes in physical activity modified the associations between changes in miR-19a-3p and ASCVD risk. A greater decrease in miR-19a-3p was significantly associated with a greater reduction in ASCVD among participants with an increase in physical activity from baseline to 6 months. These positive associations were reversed and not significant among participants with no change/decrease in physical activity and moderate/great amount of sleep disturbance.

Conclusions: In conclusion, decreased circulating miR-19 levels induced by dietary weight-loss interventions were related to a significant reduction in ASCVD risk, and such associations were more evident in people with no/slight amount of sleep disturbance and an increase in physical activity.

Degree of Joint Risk Factor Control and Incident Heart Failure in Hypertensive Patients

BACKGROUND

Heart failure (HF) is a major complication in patients with hypertension.

OBJECTIVES

This study aimed to investigate the extent to which joint risk factor control could attenuate hypertension-related excess risk of HF.

METHODS

The study included a total of 75,293 participants with diagnosed hypertension from the UK Biobank and matched with 256,619 nonhypertensive control subjects, followed up until May 31, 2021. The degree of joint risk factor control was assessed on the basis of the major cardiovascular risk factors, including blood pressure, body mass index, low-density lipoprotein cholesterol, hemoglobin A1c, albuminuria, smoking, and physical activity. The Cox proportional hazards models were used to estimate associations between the degree of risk factor control and risk of HF.

RESULTS

Among hypertensive patients, joint risk factor control showed an association with a stepwise reduction of incident HF risk. Each additional risk factor control was related to a 20% lower risk, and the optimal risk factor control (controlling ≥6 risk factors) was associated with a 62% lower risk (HR: 0.38; 95% CI: 0.31-0.45). In addition, the study found that the hypertension-related excess risk of HF among participants jointly controlling ≥6 risk factors were even lower than in nonhypertensive control subjects (HR: 0.79; 95% CI: 0.67-0.94). The protective associations of joint risk factor control and risk of incident HF were broadly stronger among men than women and among medication users than nonusers (P for interaction < 0.05).

CONCLUSIONS

The joint risk factor control is associated with a lower risk of incident HF in an accumulative and sex-specific manner. Optimal risk factor control may eliminate hypertension-related excess risk of HF.

Echocardiography-Based Cardiac Structure Parameters for the Long-term Risk of End-Stage Kidney Disease in Black Individuals: The Atherosclerosis Risk in Communities Study

OBJECTIVE

To assess whether echocardiographic parameters of left ventricular (LV) structure and function relate to the long-term risk of incident end-stage kidney disease (ESKD).

PATIENTS AND METHODS

We conducted a prospective cohort study analyzing 2137 Black participants from the Jackson site of the Atherosclerosis Risk in Communities Study from January 1, 1993, through July 31, 2017. Echocardiographic parameters of LV structure and function were obtained from 1993 to 1995. The primary outcome incident ESKD was identified through the linkage to the United States Renal Data System. Cox proportional hazards models were used to estimate the hazard ratios (HRs) according to each echocardiographic parameter.

RESULTS

There were 117 incident ESKD cases during a median follow-up of 22.2 (interquartile range, 15.0-23.3) years. Multivariable Cox models revealed that a higher LV mass index was significantly associated with the risk of ESKD (HR, 2.38; 95% CI, 1.21 to 4.68 for highest vs lowest quartile, P = 0.012). The HRs were significant and even higher for LV posterior wall thickness, with slightly higher HRs when their measures in end-systole (HR for highest vs lowest quartile, 4.38; 95% CI, 1.94 to 9.92, P < 0.001) vs end-diastole (HR, 3.50; 95% CI, 1.53 to 8.01, P = 0.003) were used. The associations were not significant for LV function parameters.

CONCLUSION

In Black individuals residing in the community, echocardiographic parameters of LV structure, including LV wall thickness, were robustly associated with the risk of subsequently incident ESKD. These results have potential implications for novel prevention and management strategies for persons with abnormal LV structure.

Lipoprotein(a) and Subclinical Vascular and Valvular Calcification on Cardiac Computed Tomography: The Atherosclerosis Risk in Communities Study

Background Lipoprotein(a) (Lp(a)) is a potent causal risk factor for cardiovascular events and mortality. However, its relationship with subclinical atherosclerosis, as defined by arterial calcification, remains unclear. This study uses the ARIC (Atherosclerosis Risk in Communities Study) to evaluate the relationship between Lp(a) in middle age and measures of vascular and valvular calcification in older age. Methods and Results Lp(a) was measured at ARIC visit 4 (1996-1998), and coronary artery calcium (CAC), together with extracoronary calcification (including aortic valve calcium, aortic valve ring calcium, mitral valve calcification, and thoracic aortic calcification), was measured at visit 7 (2018-2019). Lp(a) was defined as elevated if >50 mg/dL and CAC/extracoronary calcification were defined as elevated if >100. Logistic and linear regression models were used to evaluate the association between Lp(a) and CAC/extracoronary calcification, with further stratification by race. The mean age of participants at visit 4 was 59.2 (SD 4.3) years, with 62.2% women. In multivariable adjusted analyses, elevated Lp(a) was associated with higher odds of elevated aortic valve calcium (adjusted odds ratio [aOR], 1.82; 95% CI, 1.34-2.47), CAC (aOR, 1.40; 95% CI, 1.08-1.81), aortic valve ring calcium (aOR, 1.36; 95% CI, 1.07-1.73), mitral valve calcification (aOR, 1.37; 95% CI, 1.06-1.78), and thoracic aortic calcification (aOR, 1.36; 95% CI, 1.05-1.77). Similar results were obtained when Lp(a) and CAC/extracoronary calcification were examined on continuous logarithmic scales. There was no significant difference in the association between Lp(a) and each measure of calcification by race or sex. Conclusions Elevated Lp(a) at middle age is significantly associated with vascular and valvular calcification in older age, represented by elevated CAC, aortic valve calcium, aortic valve ring calcium, mitral valve calcification, thoracic aortic calcification. Our findings encourage assessing Lp(a) levels in individuals with increased cardiovascular disease risk, with subsequent comprehensive vascular and valvular assessment where elevated.

Simplified hypertension screening approaches with low misclassification and high efficiency in the United States, Nepal, and India

Standard triplicate blood pressure (BP) measurements pose time barriers to hypertension screening, especially in resource‐limited settings. We assessed the implications of simplified approaches using fewer measurements with adults (≥18 years old) not using anti‐hypertensive medications from the US National Health and Nutrition Examination Survey 1999‐2016 (n = 30 614), and two datasets from May Measurement Month 2017‐2018 (n = 14 795 for Nepal and n = 6 771 for India). We evaluated the proportion of misclassification of hypertension when employing the following simplified approaches: using only 1st BP, only 2nd BP, 2nd if 1st BP in a given range (otherwise using 1st), and average of 1st and 2nd BP. Hypertension was defined as average of 2nd and 3rd systolic BP ≥140 and/or diastolic BP ≥90 mm Hg. Using only the 1st BP, the proportion of missed hypertension ranged from 8.2%–12.1% and overidentified hypertension from 4.3%–9.1%. Using only 2nd BP reduced the misclassification considerably (corresponding estimates, 4.9%–6.4% for missed hypertension and 2.0%–4.4% for overidentified hypertension) but needed 2nd BP in all participants. Using 2nd BP if 1st BP ≥130/80 demonstrated similar estimates of missed hypertension (3.8%–8.1%) and overidentified hypertension (2.0%–3.9%), but only required a 2nd BP in 33.8%–59.8% of participants. In conclusion, a simplified approach utilizing 1st BP supplemented by 2nd BP in some individuals has low misclassification rates and requires approximately half of the total number of measurements compared to the standard approach, and thus can facilitate screening in resource‐constrained settings.

Conventional and Novel Lipid Measures and Risk of Peripheral Artery Disease

OBJECTIVE

The aim of this study was to comprehensively assess the association of multiple lipid measures with incident peripheral artery disease (PAD). Approach and Results: We used Cox proportional hazards models to characterize the associations of each of the fasting lipid measures (total cholesterol, LDL-C [low-density lipoprotein cholesterol], HDL-C [high-density lipoprotein cholesterol], triglycerides, RLP-C [remnant lipoprotein cholesterol], LDL-TG [LDL-triglycerides], sdLDL-C [small dense LDL-C], and Apo-E-HDL [Apo-E-containing HDL-C]) with incident PAD identified by pertinent International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) hospital discharge codes (eg, 440.2) among 8330 Black and White ARIC (Atherosclerosis Risk in Communities) participants (mean age 62.8 [SD 5.6] years) free of PAD at baseline (1996-1998) through 2015. Since lipid traits are biologically correlated to each other, we also conducted principal component analysis to identify underlying components for PAD risk. There were 246 incident PAD cases with a median follow-up of 17 years. After accounting for potential confounders, the following lipid measures were significantly associated with PAD (hazard ratio per 1-SD increment [decrement for HDL-C and Apo-E-HDL]): triglycerides, 1.21 (95% CI, 1.08-1.36); RLP-C, 1.18 (1.08-1.29); LDL-TG, 1.18 (1.05-1.33); HDL-C, 1.39 (1.16-1.67); and Apo-E-HDL, 1.27 (1.07-1.51). The principal component analysis identified 3 components (1: mainly loaded by triglycerides, RLP-C, LDL-TG, and sdLDL-C; 2: by HDL-C and Apo-E-HDL; and 3: by LDL-C and RLP-C). Components 1 and 2 showed independent associations with incident PAD.

CONCLUSIONS

Triglyceride-related and HDL-related lipids were independently associated with incident PAD, which has implications on preventive strategies for PAD. However, none of the novel lipid measures outperformed conventional ones. Graphic Abstract: A graphic abstract is available for this article.

Cardiovascular Disease and Coronavirus Disease 2019: Epidemiology, Management, and Prevention

Purpose of Review

Coronavirus disease 2019 (COVID-19) has become a global pandemic associated with significant morbidity and mortality. This review summarizes findings up to date on the relationship between cardiovascular disease (CVD) and COVID-19.

Recent Findings

Preexisting CVD is a common condition among patients with COVID-19 and is associated with increased disease severity and mortality. Conversely, COVID-19 has various clinical manifestations on cardiovascular system, including thrombotic events and cardiac dysfunction. The pandemic has impacted healthcare utilization among patients with CVD, which may have led to potential delay in access to the healthcare system during acute events not directly COVID-19-related.

Summary

While COVID-19 vaccine is being developed and distributed, controlling CVD risk factors and adherence to recommendations of existing immunization (e.g., influenza vaccine) are key in protecting the health of individuals with CVD during the COVID-19 pandemic. Further research is needed to understand the epidemiological and pathophysiological basis for the interaction between CVD and COVID-19.

Cardiorespiratory responses to fine particles during ambient PM2.5 pollution waves: Findings from a randomized crossover trial in young healthy adults

BACKGROUND

PM_2.5 pollution waves (PPWs) are severe air pollution events with extremely high-level concentration of ambient PM_2.5. PPWs, such as haze days, were suggested to be associated with increased cardiopulmonary mortality and morbidity. However, the biological mechanism response to ambient PM_2.5 during PPWs is still unclear.

METHODS

A randomized crossover trial was conducted on 29 healthy young adults. Repeated health measurements were performed before, during and after two typical PPWs under filtered and sham indoor air purification, with a washout interval of at least 2 weeks. Health parameters including blood pressure (BP), pulmonary function, fractional exhaled nitric oxide (FeNO) and circulating biomarkers which reflect platelet activation, blood coagulation and systematic oxidative stress were measured.

RESULTS

Ambient PM_2.5 levels elevated apparently during PPWs. Under sham purification, significant increase in FeNO and soluble P-selectin (sP-selectin) and decreases in pulmonary function were observed from pre-PPWs period to during-PPWs period. The changes in health biomarkers as mentioned above became attenuated and insignificant under filtered condition. For instance, sP-selectin increased by 12.0% (95% CI: 3.8%, 20.8%) during-PPWs periods compared with pre-PPWs periods under sham purification, while non-significant change was observed under filtered condition. Significant associations between time-weighted personal PM_2.5 exposure and increased levels of health biomarkers including FeNO, sP-selectin, oxidized low-density lipoprotein (ox-LDL) and 8-isoprostane (8-isoPGF2α) were found.

CONCLUSION

PPWs could affect cardiopulmonary health through systematic oxidative stress, platelet activation and respiratory inflammation in healthy adults, and short-term indoor air purification could alleviate the adverse cardiopulmonary effects.

Joint Effect of Non-invasive Central Systolic Blood Pressure and Peripheral Systolic Blood Pressure on Incident Hypertension in a Chinese Community-based Population

Central blood pressure level is not always consistent with peripheral blood pressure level, and especially their joint effect on incident hypertension is not well established. A total of 1607 non-hypertensive subjects from an atherosclerosis cohort in Beijing, China were included. Central systolic blood pressure (cSBP) was obtained using Omron HEM-9000AI machine and peripheral systolic blood pressure (pSBP) was measured using Omron HEM-7117 electronic sphygmomanometer, separately. Hypertension was defined as BP ≥ 140/90 mmHg or self-reported hypertension or taking any antihypertension drugs at the follow-up survey. After a median follow-up of 2.3 years, incident hypertension was 13.1%. Every 1 standard deviation increase of cSBP and pSBP was associated with 1.98 (95%CI: 1.69-2.33) and 2.84 (95%CI: 2.30-3.52) times of incident hypertension after adjustment for confounders. Moreover, hypertension risk in single pSBP ≥ 120 mmHg group, single cSBP ≥ 120 mmHg group, and both pSBP and cSBP ≥ 120 mmHg group was 2.83 (95%CI: 0.98-8.16), 3.28 (95%CI: 1.24-8.70), and 11.47 (95%CI: 4.97-26.46) times higher than both pSBP and cSBP < 120 mmHg group, respectively. The joint effect of cSBP and pSBP is superior to either cSBP or pSBP to predict incident hypertension in a Chinese community-based population. Screening of central blood pressure should be considered in non-hypertensive population for the purpose of primary intervention, especially for subjects with pSBP ≥ 120 mmHg.

Curtailing unnecessary vancomycin usage in a hospital with high rates of methicillin resistant Staphylococcus aureus infections

AIMS

To implement and monitor the effectiveness of a strategy to curb unnecessary use of vancomycin and teicoplanin for inpatients in a teaching hospital/tertiary referral centre where 33% of S. aureus isolates (72% from ICU patients) were methicillin resistant.

METHODS

A sample of 182 vancomycin/teicoplanin inpatient prescriptions surveyed, revealed that only 31 (17%) conformed with Centre for Disease Control (CDC) guidelines. Following education (ward-rounds, bulletins) on appropriate CDC based guidelines for prescribing glycopeptides directed at relevant clinicians, 'Immediate Concurrent Feedback' (ICF) was gradually deployed throughout the hospital. This entailed review of respective inpatient records on the next working day. If the indication was deemed not to conform with our guidelines, the prescriber was issued a memo (copied to the supervising doctor). Each memo detailed the 'errant' incident, listed appropriate indications and explicitly advised desisting from such prescribing and suggested alternative therapy if necessary. Corresponding glycopeptide usage data for our hospital and others in Hong Kong were retrieved and analysed as were samples of records of our inpatients with staphylococcal septicaemia (pre and during ICF).

RESULTS

Compared with baseline values, during 2 years of ICF, inpatient prescribing of vancomycin and teicoplanin deemed to conform increased to 71% (773/1086); difference 54% (P < 0.0001, 95% CIs 47-62%). Corresponding average monthly usage (DDDs/1000 admissions) decreased from 76 (pre-ICF) to 45; mean difference 31 (P < 0.0001, 95% CIs 24, 38). Mortality from staphylococcal bacteraemia remained unchanged. No comparable changes in glycopeptide usage ensued in comparator hospitals.

CONCLUSIONS

ICF can be used safely to curb irrational overuse of vancomycin and teicoplanin in a hospital with high methicillin resistant S. aureus infection rates.

Increasing use of inhaled steroids associated with declining asthma mortality

Increasing worldwide asthma prevalence and mortality has led to greater advocacy of inhaled agents, especially steroids. To determine whether corresponding drug usage trends had ensued locally, wholesale data (expressed as defined daily doses (DDDs)/1000 inhabitants/day) were compared for inclusive periods 1984-1986 and 1992-1994. Whereas absolute usage of anti-asthmatics increased by 79%, proportional inhaled usage increased markedly, especially of steroids (571%) and in hospitals. An odds ratio trend analysis revealed asthma mortality from 1992 onward had declined, particularly in males (p < 0.001). In Hong Kong, despite increasing asthma prevalence, more intensive use of anti-asthmatic drugs (especially inhaled steroids) was associated with declining asthma mortality.

Antiulcer drug prescribing in hospital successfully influenced by "immediate concurrent feedback"

OBJECTIVE

To determine whether immediate concurrent feedback (ICF) focused on inpatient omeprazole prescribing achieved more rational and cost-effective antiulcer drug prescribing and usage.

METHODS

In a 1400-bed teaching hospital, an audit (by specially trained personnel) was conducted to monitor inpatient prescribing of omeprazole (1) in preference to H2-antagonists and other drugs according to agreed criteria (Helicobacter pylori eradication, severe reflux esophagitis, rapid ulcer healing deemed urgent because of severe symptoms or complications, high-dose steroid therapy of > or =30 mg/day prednisolone) and (2) appropriateness of intravenous dosing (oral route not feasible or contraindicated). After baseline monitoring for 1 month, followed by relevant antiulcer drug therapy education, ICF was instituted for 1 year. This entailed explanatory memoranda requesting a change in prescribing issued to the respective medical teams of patients whose omeprazole prescription did not "conform." The main outcomes of the study were omeprazole prescription numbers per month and the proportion conforming, defined daily doses of antiulcer drugs used and corresponding expenditures, and pertinent antiulcer drug utilization data from 9 other local hospitals.

RESULTS

Baseline omeprazole prescribing conformed in 32 of 173 (18%) of the patients compared with 451 of 546 (83%) during institution of ICF (P < 0001; chi2 test). Correspondingly, average overall omeprazole and ranitidine usage (inpatient and outpatient) and expenditure decreased (44% and 45%, respectively); collectively, use of less expensive alternatives increased about 61%. Estimated savings averaged about HK$150,000 ($20,000) per month. No comparable changes in usage were noted in 9 other local hospitals.

CONCLUSION

Regarding hospital antiulcer drugs, this ICF strategy was associated with more rational prescribing and usage, and an important saving of resources.

Bronchodilator responses to salbutamol using diskhaler versus metered-dose inhaler

In adults inhaling salbutamol via metered-dose inhalers (MDls) 200 microg doses are recommended, but with diskhalers the manufacturer advocates 400 rather than 200 microg doses. To assess this advice, a partially double-blind, placebo-controlled salbutamol dose response, crossover study (also incorporating MDI doses) was conducted in 12 mild/moderate asthmatics. After active treatment, mean peak expiratory flow rate (PEFR) increments yielded no clinically or statistically significant differences; compared to placebo, respective median differences in PEFR increments (95% Cls) were 10 (-10, 50), 20 (0, 50), and 15 (0, 30) following 400 and 200 microg via diskhalers and 200 microg via MDls. Diskhalers are a suitable alternative for patients with poor MDI technique, but the use of 400 rather than 200 microg salbutamol doses is not supported by evidence.

Inability of physicians to use metered-dose inhalers

The effectiveness of antiasthmatic therapy with metered-dose inhalers (MDIs) is usually limited by defective inhalational technique. This study surveyed the MDI inhalation performance and knowledge of 100 physicians whose performance (demarcated into six stages) and knowledge scores correlated (r = 0.33, p < 0.001). Inhalation performance scores for shaking the canister, full expiration prior to using the MDI, breath holding thereafter, and positioning of the mouth-piece correlated with their corresponding knowledge scores (p < or = 0.02). Training of physicians entailing actual instruction and supervision of inhalational maneuvers may enhance the ability of doctors to use MDIs and facilitate better patient supervision.

Hospital antibiotic prescribing successfully modified by 'immediate concurrent feedback'

1. To determine the effectiveness of ongoing immediate concurrent feedback (ICF) in minimizing 'inappropriate' sultamicillin or co-amoxiclav prescribing via the parenteral route (i.e. when the oral route was accessible and not contraindicated), a prospective controlled audit was carried out on hospital inpatients over a 20 month period. 2. After an education programme to promote oral rather than unnecessary intravenous (i.v.) use of sultamicillin, co-amoxiclav and certain other drugs, an ongoing ICF strategy was instituted. 3. ICF entailed issue of memos on the following day to prescribers of i.v. sultamicillin or co-amoxiclav for inpatients in whom this route was deemed 'inappropriate', by a specially trained nurse using strict objective criteria. The memos recommended oral prescribing (particularly of co-amoxiclav, currently the less expensive alternative). 4. After starting ICF, there were consistent, clinically and statistically significant reductions in the monthly proportions of (i) admissions prescribed i.v. sultamicillin or co-amoxiclav (38% P < 0.001), (ii) those in whom the route was 'inappropriate' (75%, P < 0.001), and (iii) corresponding ratios of i.v./oral usage and expenditure, oral sultamicillin/co-amoxiclav usage and expenditure, as well as total and per admission expenditure on i.v. forms (> or = 43%, P < 0.01). 5. For i.v. cefuroxime (for which there was no ICF) and its oral counterpart cefuroxime-axetil, there were no comparable changes in usage or expenditure. 6. This simple, ongoing ICF strategy was effective and well accepted; estimated net monthly savings being HK$26-30,000.

Investigation of nimodipine pharmacokinetics in Chinese patients with acute subarachnoid haemorrhage

Nimodipine pharmacokinetics was investigated in 12 Chinese patients with acute subarachnoid haemorrhage receiving an IV infusion of 1.6 or 2 mg/h (based on estimated body weight) for 10 days. Peripheral venous blood samples were collected for up to 4 days and plasma nimodipine was assayed by GC/ECD. The mean value was taken as the steady state concentration (Css) and Clearance (CL) (hourly dose/Css) was calculated. Eight survivors were given oral nimodipine (60 or 90 mg) every 6h (based on body weight), blood was sampled over 6 h and the plasma nimodipine level determined. The values for Css, CL and CL.kg-1 were 33.5 micrograms.l-1, 58 l.h-1 and 1.0 l.h-1 x kg-1 respectively; in survivors receiving the drug orally, bioavailability of the 30 mg tablet was 9%. In one very sick patient given crushed tablets by naso-gastric tube, the AUC was very low; in vitro studies indicated that adsorption of nimodipine by the tubing was unlikely to have been the cause. The pharmacokinetic findings in Chinese patients are comparable to previously reported values in Caucasians.

Treatment of acute cortical infarct with intravenous glycerol. A double-blind, placebo-controlled randomized trial

BACKGROUND AND PURPOSE

This clinical trial investigates the effectiveness of intravenous glycerol therapy in patients with acute cortical infarction in whom intracerebral hemorrhage was rigorously excluded.

METHODS

Within 48 hours of symptoms from their first ischemic stroke, 113 hospital inpatients were randomized into the trial, provided that hemorrhage was excluded by computed tomography and informed consent was obtained. Patients were stratified into alert, semicoma, and coma groups using the Glasgow Coma Scale. Treatment was allocated according to a double-blind, randomized protocol; 56 patients received 500 mL of 10% glycerol in saline over 4 hours on 6 consecutive days, and 57 patients received corresponding placebo treatment with saline. Using a variety of objective scoring systems, patient follow-up was up to 6 months.

RESULTS

Corresponding measures of outcome in the glycerol and placebo groups were similar. At 6 months, respective mortality rates were 17 of 56 and 16 of 57, and mean +/- SD improvements in scores were 9.98 +/- 14.40 vs 10.51 +/- 12.68 (long-term), 1.12 +/- 7.20 vs 1.57 +/- 6.30 (prognostic), -1.94 +/- 5.53 vs -2.06 +/- 5.34 (Glasgow Coma Scale), and 21.72 +/- 23.40 vs 11.94 +/- 18.10 (Barthel Index rating in survivors). Hemolysis (generally subclinical) was the only adverse effect.

CONCLUSIONS

There was no clinically or statistically significant difference in outcome between the groups; a trend toward greater functional recovery among survivors was evident after treatment with glycerol.

An audit of antiasthmatic drug inhalation technique and understanding

Inhaled rather than oral antiasthmatic therapy is accepted as more advantageous but depends on patient technique and understanding. In 74 asthmatic outpatients, technique using metered-dose inhaler (MDI) was poor; in 56 patients inhaling beta-agonist, the mean peak expiratory flow rate (PEFR) increase was only 15 L/min (6%) greater than in 18 controls, p < 0.05, 95% confidence intervals 2-27 L/min or 2-11%. Tilting the head back and actuation "stopping" inspiration produced the least favorable PEFR responses; taken together, regression analysis yielded a statistically significant negative correlation with absolute or percentage PEFR change (R2 = 0.15; p < 0.02). Patients were unclear about which drugs to inhale as required or regularly. Among 19 patients reassessed inhaling beta-agonist, only 8 had baseline PEFR values within 10% of each other during both assessments. In the latter, the mean postinhalation PEFR increase was 36 L/min (or 13%) greater than the corresponding increase (or % change) at first assessment, p = 0.05 (0.08), 95% confidence intervals 0-73 L/min (-2 to 29%). Thus, MDI users should avoid tilting the head back, actuation stopping inhalation, and be more aware of prophylactic (steroid) versus symptomatic (beta-agonist) treatment.

Treatment of acute cerebral hemorrhage with intravenous glycerol. A double-blind, placebo-controlled, randomized trial

BACKGROUND AND PURPOSE

Hitherto, treatment of acute cerebral hemorrhage with intravenous glycerol has not been evaluated in rigorous clinical studies with sufficient patient numbers.

METHODS

We undertook a double-blind, stratified and randomized, placebo-controlled clinical trial. Only patients with a first stroke admitted to the hospital within 24 hours after onset of symptoms were recruited, provided computed tomography confirmed hemorrhage and informed consent was obtained. After stratification into alert, semicoma, and coma subgroups using the Glasgow Coma Scale, 107 patients received active treatment (500 ml of 10% glycerol in saline by intravenous infusion over 4 hours on 6 consecutive days) and 109 were given corresponding saline treatment. Using a variety of objective scoring systems, patients were followed up for up to 6 months.

RESULTS

At follow-up, all measures of outcome in the treated and control groups were very similar. At 6 months, respective mortality rates were 37 of 107 and 33 of 109. Corresponding mean +/- SD improvements in Scandinavian Stroke Study Group scores were 8.35 +/- 16.9 versus 11.55 +/- 15.6 (long-term) and 0.64 +/- 7.3 versus 2.40 +/- 6.9 (prognostic), and improvements in the Barthel Index ratings were 10.72 +/- 24.7 versus 13.95 +/- 23.3, respectively. Glasgow Coma Scale score improvements in the survivors were 0.81 +/- 1.5 and 1.16 +/- 1.7 in the treated and control groups, respectively. Hemolysis (generally subclinical) was the only adverse effect of glycerol noted.

CONCLUSIONS

In the absence of any clinically or statistically significant difference in outcome between the treated and control groups, this trial provides no justification for glycerol therapy following acute cerebral hemorrhage.

Audit exposes flawed blood sampling for "digoxin levels"

Therapeutic "digoxin level" monitoring in selected wards was audited. Time elapsing between the last dose and blood sampling was considered appropriate if greater than or equal to 6 h. If such details were not entered on the requisition, the maximum time elapsing was estimated as "appropriate" or "inappropriate" from the time samples were logged into the laboratory and the time the last dose was entered in the patient's treatment sheet. In 22 requisitions detailing sampling time, nine were considered inappropriate. In an additional 150 instances, timing was estimated as inappropriate in 45. Among the 118 requests where timing (estimated or labelled) was appropriate, available plasma digoxin concentrations yielded a mean of 1.0 nM, compared to 1.6 nM in the corresponding 54 patients with premature sampling; this difference was both clinically and statistically significant (95% confidence limits 0.8-1.2 and 1.3-1.9 nM, respectively, p less than 0.001). Premature blood sampling for digoxin levels was common and associated with higher concentrations than when appropriate. Such inappropriate timing may not have serious consequences, but digoxin levels are a matter of record and are used for teaching; due attention to timing could provide more reliable information and avoid wasting valuable resources.

Actions of FRC-8653 on smooth muscle cells of the rabbit mesenteric artery

In ring preparations of the rabbit mesenteric artery, the Ca-contraction, but not the noradrenaline (NA)-contraction, was inhibited by FRC-8653 (10(-9)-10(-5) M) in a concentration-dependent manner, although with a potency 50-100 times weaker than that of nicardipine. The actions of FRC-8653 on Ca-contraction appeared more slowly (over 1 hr) than those of nicardipine. FRC-8653 (up to 10(-5) M) and nicardipine (up to 10(-7) M) did not change the resting membrane potential of smooth muscles. The amplitude of the evoked excitatory junction potential (e.j.p.) was inhibited by FRC-8653, but not by nicardipine, with no alteration in the facilitation process of the e.j.p.s. The inhibition by FRC-8653 of the e.j.p. appeared rapidly and was reversible. FRC-8653 inhibited the membrane depolarization of smooth muscles elicited by ATP, but not by NA or high [K+]o solution. ATP-induced contractions were also inhibited by FRC-8653. The amplitudes of action potentials evoked by current stimuli were decreased by FRC-8653, with no significant change in the electrotonic potentials. Thus, FRC-8653 has properties similar to those of the dihydropyridine Ca-antagonists, but differs from them in that 1) its inhibitory actions on Ca influx appear slowly and 2) sympathetic transmission is inhibited, possibly by inhibition of the postjunctional events for e.j.p. generation.

Recognition of the tRNA-like structure in tobacco mosaic viral RNA by ATP/CTP:tRNA nucleotidyltransferases from Escherichia coli and Saccharomyces cerevisiae

The 3'-terminal tRNA-like structure of the tobacco mosaic virus RNA interacts with ATP/CTP:tRNA nucleotidyltransferases from Escherichia coli or yeast in much the same manner as do tRNAs. Primary sites of interaction cluster near the 3' end and in the loop proposed to be analogous to the psi-loop of a tRNA. Some modified bases in the tRNA-like structure inhibit interaction with nucleotidyltransferase, yet the analogous bases in a tRNA do not. The location of some of these nucleotides within the analog to the psi-loop suggests that this structure differs slightly from its counterpart in a tRNA. The location of other such bases in the helical stem near the 3' end can be explained if the pseudoknot is disrupted by these modified bases or if the tertiary structure of the RNA is altered in the enzyme-RNA complex. A partially denatured secondary structure that persists on denaturing gels is proposed.

Lack of association between slow acetylator status and spontaneous lupus erythematosus

The Chinese in Southeast Asia are recognized as a population group that has a relatively high prevalence of rapid "acetylators" and a relatively high incidence of systemic lupus erythematosus. This study was designed to evaluate the possibility that there were environmental lupus erythematosus provocative substances eliminated by acetylation that resulted in a preponderance of slow acetylators among patients with the disease. We compared acetylator status in 36 Chinese women with mild, stable, and confirmed lupus erythematosus and 36 healthy control subjects matched for age, sex, and ethnic origin. Acetylator status was determined by use of HPLC to assay 5-acetylamino-6-formylamino-3-methyluracil/methylxanthine (AFMU/MX) and AFMU/(AFMU + MX) ratios in urine 1 to 4 hours after drinking a strong cup of coffee (caffeine). By use of parametric and nonparametric methods of analysis, the frequency distribution of AFMU/MX and AFMU/(AFMU + MX) ratios in both the patients and control subjects were determined to be very similar. Thus there was no association between slow acetylator status and lupus erythematosus in the study subjects.

Investigation of intravascular haemolysis during treatment of acute stroke with intravenous glycerol

1. In patients with acute strokes entering a large ongoing randomised double-blind controlled trial of intravenous glycerol therapy, the extent and pathogenesis of any ensuing haemolysis were evaluated using standard clinical investigations and in vitro techniques. 2. Twenty patients received 10% glycerol in saline (500 ml over 4 h on 6 consecutive days) and 15 received corresponding control treatment with saline. 3. Intravascular haemolysis was evident after the first infusion; compared with the controls the glycerol group had i) a greater mean reduction in serum haptoglobin concentration (P less than .05), and ii) a greater proportion exhibiting haemoglobinaemia (P = 0.03). 4. After 6 days of glycerol treatment, the mean reduction in haemoglobin concentration was only 0.8 g more than in controls; this difference being neither clinically nor statistically significant. 5. Glycerol therapy was not associated with haemoglobinuria, renal insufficiency or disseminated intravascular coagulation. 6. Exposure of red blood cells to 1-10% glycerol in vitro did not induce haemolysis per se; on re-exposure to lower concentrations lysis ensued provided a minimum osmotic gradient was present. 7. Whilst taking standard dosage regimes of glycerol, the stroke patients we studied manifested a degree of intravascular haemolysis but its consequences were not clinically significant; lysis probably ensued after venous blood acquiring high glycerol concentrations mixed with blood containing little or no glycerol.

Cephalosporin and aminoglycoside utilization in different parts of the world

Cephalosporin and aminoglycoside utilization in Hong Kong during 1984, 1985 and 1986, were evaluated from wholesale data and compared with corresponding Swedish statistics and with UK data from a survey of non-hospital prescriptions. Details regarding each drug and category were collated, adjusted for population and if appropriate expressed as defined daily doses (DDDs)/1000 inhabitants/day. With respect to cephalosporins: (a) overall sales (especially those of the newer and more expensive parenteral drugs) were increasing; (b) parenteral sales were much larger in Hong Kong hospitals than in the community (up to about 106 versus 16 kg/million inhabitants/year respectively), but in Sweden they were comparable (up to about 38 and 41 kg/million inhabitants/year respectively); (c) non-hospital oral utilization appeared greater in the UK than in Sweden and Hong Kong (up to about 0.7, 0.4 and 0.4 DDDs/1000 inhabitants/day respectively); (d) oral sales to hospitals were greater in Hong Kong than Sweden (up to 0.3 compared to 0.1 DDDs/1000 inhabitants/day respectively) and (e) oral paediatric formulations (liquids) were most popular in Hong Kong, a higher proportion of children in Hong Kong being one possible reason. Non-hospital sales of gentamicin and kanamycin in Hong Kong were much greater than in Sweden (up to about 0.20 and 0.06 vs. 0.01 and 0.00 DDDs/1000 inhabitants/day respectively), whereas UK utilization appeared almost non-existent. Topical neomycin sales in Hong Kong were much more popular than in Sweden (up to about 60 vs. 9 g/million inhabitants/day). These regional differences in antibiotic utilization may be related to respective health care systems (and thus the affordability and availability of drugs) and prescribing preferences (cultural and/or promoted by drug companies), quite apart from possible differences in drug efficacy, drug tolerance and the prevalence and severity of various infections.

Pattern of anti-asthmatic drug utilization in Hong Kong compared to other parts of the world

Inhaled drugs are now considered first line agents for the treatment of asthma, whereas oral beta-agonists, theophylline and its derivatives have been relegated to a secondary role. To determine whether current prescribing in Hong Kong conforms to these recommendations, we have evaluated anti-asthmatic drug utilization in the territory as reflected by 1984-86 drug sales (courtesy Medical and Health Department, Hong Kong). Sales/prescription statistics were also obtained from corresponding agencies of other governments and from published literature. If appropriate, data for comparison was expressed as defined daily doses (DDDs) per 1000 inhabitants per day. In contrast to the pattern of utilization in several developed nations, in Hong Kong (a) oral anti-asthmatic agents (particularly beta agonists) were more commonly utilized than inhaled drugs, and (b) inhaled therapy mainly consisted of non-selective beta-agonists, steroids being very rare. Further education is required to improve anti-asthmatic drug utilization patterns in the community.

An assessment of drug information sheets for diabetic patients: only active involvement by patients is helpful

Insulin/sulphonylurea-treated diabetics attending a busy university diabetic clinic were studied to determine whether issuing drug information sheets and/or age influenced understanding and behaviour regarding their disease and its treatment, especially with respect to avoiding hypoglycaemia. Patients were each asked 10 basic questions (each correct answer scoring 1), stratified by age (20 were less than or equal to 45 years and 91 greater than 45 years). According to a single-blind randomised protocol, they were issued or not issued with drug information sheets (providing information to correctly answer all 10 questions). After 2-3 months, 107 (88 aged greater than 45 years) were retested and asked whether they recalled an information sheet, read it themselves or had it read to them. Whether or not patients received sheets, corresponding mean aggregate scores were very similar in both age groups and there was no correlation with age. Second test scores yielded clinically and statistically significant increments in both the sheet and no sheet groups, respective mean aggregate scores increasing from 4.48 to 5.80 and 5.14 to 6.27 (P less than 0.001). Among patients issued with sheets, 32 who recalled reading them achieved the greatest improvement in mean scores (4.53 to 6.16, P less than 0.001). Active interaction/communication (participation in first test, recall and reading of information sheet) had a favourable educational impact irrespective of age, but merely issuing drug information sheets had no benefit.

Chemoprophylaxis with oral amoxycillin against bacterial endocarditis: when should second doses be administered after dentistry?

The adequacy of serum bactericidal activity after oral amoxycillin given as prophylaxis against infective endocarditis was studied using a double blind randomised protocol in healthy volunteers having dentistry. One hour before their procedure 38 patients received 3 g amoxycillin syrup and 12 received matching placebo. Venous blood samples were drawn before and one and nine hours after dosing and serum amoxycillin concentrations determined using a standard bioassay. Samples containing amoxycillin had inhibitory titres measured against two reference isolates of viridans streptococci known to have caused infective endocarditis. The susceptibility to amoxycillin of one strain was high and the other low, respective minimal bactericidal and inhibitory concentrations being 0.08 and 0.04 mumol/l (0.03 and 0.015 microgram/ml) and 2.74 and 1.37 mumol/l (1 and 0.5 microgram/ml). Amoxycillin was detected in only post-treatment samples of patients given the active drug. There were no significant correlations between one or nine hour drug concentrations and age or physical characteristics, nor was there any relation to preceding food consumption. Correlations between drug concentrations at one and nine hours were weak (r = 0.34; p less than 0.05), but between corresponding drug concentrations and serum inhibitory titres there were consistent correlations (r = 0.46-0.48; p less than 0.005). Against the low susceptibility reference isolate bactericidal amoxycillin concentrations were encountered in only 20 of the 38 nine hour samples (95% confidence limits 34% and 66%). When repeat doses of amoxycillin are indicated after dentistry they should be given about four hours later, not eight hours later as commonly practised.