Alex Chang

Prof. Alex Chang


Research Focus & Metrics

Academic Career Length

37Years (1990-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 February 2024 in Circulation
Verified
Journal Article
Closed access
SKSadiya S. Khan
Sadiya S. Khan
KMKunihiro Matsushita
Kunihiro Matsushita
YSYingying Sang
Yingying Sang
SBShoshana H. Ballew
Shoshana H. Ballew
MGMorgan E. Grams
Morgan E. Grams
FGfor the Chronic Kidney Disease Prognosis Consortium and the American Heart Association Cardiovascular-Kidney-Metabolic Science Advisory Group
for the Chronic Kidney Disease Prognosis Consortium and the American Heart Association Cardiovascular-Kidney-Metabolic Science Advisory Group
BACKGROUND: Multivariable equations are recommended by primary prevention guidelines to assess absolute risk of cardiovascular disease (CVD). However, current equations have several limitations. Therefore, we developed and validated the American Heart Association Predicting Risk of CVD EVENTs (PREVENT) equations among US adults 30 to 79 years of age without known CVD. METHODS: The derivation sample included individual-level participant data from 25 data sets (N=3 281 919) between 1992 and 2017. The primary outcome was CVD (atherosclerotic CVD and heart failure). Predictors included traditional risk factors (smoking status, systolic blood pressure, cholesterol, antihypertensive or statin use, and diabetes) and estimated glomerular filtration rate. Models were sex-specific, race-free, developed on the age scale, and adjusted for competing risk of non-CVD death. Analyses were conducted in each data set and meta-analyzed. Discrimination was assessed using the Harrell C-statistic. Calibration was calculated as the slope of the observed versus predicted risk by decile. Additional equations to predict each CVD subtype (atherosclerotic CVD and heart failure) and include optional predictors (urine albumin-to-creatinine ratio and hemoglobin A1c), and social deprivation index were also developed. External validation was performed in 3 330 085 participants from 21 additional data sets. RESULTS: Among 6 612 004 adults included, mean±SD age was 53±12 years, and 56% were women. Over a mean±SD follow-up of 4.8±3.1 years, there were 211 515 incident total CVD events. The median C-statistics in external validation for CVD were 0.794 (interquartile interval, 0.763–0.809) in female and 0.757 (0.727–0.778) in male participants. The calibration slopes were 1.03 (interquartile interval, 0.81–1.16) and 0.94 (0.81–1.13) among female and male participants, respectively. Similar estimates for discrimination and calibration were observed for atherosclerotic CVD– and heart failure–specific models. The improvement in discrimination was small but statistically significant when urine albumin-to-creatinine ratio, hemoglobin A1c, and social deprivation index were added together to the base model to total CVD (ΔC-statistic [interquartile interval] 0.004 [0.004–0.005] and 0.005 [0.004–0.007] among female and male participants, respectively). Calibration improved significantly when the urine albumin-to-creatinine ratio was added to the base model among those with marked albuminuria (>300 mg/g; 1.05 [0.84–1.20] versus 1.39 [1.14–1.65]; P =0.01). CONCLUSIONS: PREVENT equations accurately and precisely predicted risk for incident CVD and CVD subtypes in a large, diverse, and contemporary sample of US adults by using routinely available clinical variables.

1 February 2016 in JAMA Internal Medicine
Verified
Journal Article
Open access
PDF file
BLBenjamin Lazarus
Benjamin Lazarus
YCYuan Chen
Yuan Chen
FWFrancis P. Wilson
Francis P. Wilson
YSYingying Sang
Yingying Sang
ACAlex Chang
Alex Chang
MGMorgan E. Grams
Morgan E. Grams
Chronic kidney disease (CKD) affects approximately 13.6% of adults in the United States,1 is associated with a substantially increased risk of death and cardiovascular events,2 and accounts for a disproportionately large burden on the financial resources of Medicare.1 The increasing prevalence of CKD among communities cannot be fully explained by trends in known risk factors, such as diabetes mellitus and hypertension, suggesting that other variables may contribute to the disease process.3,4 Medication use may be a potential factor, particularly given tendencies toward polypharmacy.5 Identifying iatrogenic risk factors for CKD may help to promote the rational use of medications and reduce the burden of CKD worldwide.

4 February 2016 in New England Journal of Medicine
Verified
Journal Article
Closed access
PDF file
MGMorgan E. Grams
Morgan E. Grams
YSYingying Sang
Yingying Sang
ALAndrew S. Levey
Andrew S. Levey
KMKunihiro Matsushita
Kunihiro Matsushita
SBShoshana Ballew
Shoshana Ballew
AGAmit X. Garg
Amit X. Garg
Evaluation of candidates to serve as living kidney donors relies on screening for individual risk factors for end-stage renal disease (ESRD). To support an empirical approach to donor selection, we developed a tool that simultaneously incorporates multiple health characteristics to estimate a person’s probable long-term risk of ESRD if that person does not donate a kidney. We used risk associations from a meta-analysis of seven general population cohorts, calibrated to the population-level incidence of ESRD and mortality in the United States, to project the estimated long-term incidence of ESRD among persons who do not donate a kidney, according to 10 demographic and health characteristics. We then compared 15-year projections with the observed risk among 52,998 living kidney donors in the United States. A total of 4,933,314 participants from seven cohorts were followed for a median of 4 to 16 years. For a 40-year-old person with health characteristics that were similar to those of age-matched kidney donors, the 15-year projections of the risk of ESRD in the absence of donation varied according to race and sex; the risk was 0.24% among black men, 0.15% among black women, 0.06% among white men, and 0.04% among white women. Risk projections were higher in the presence of a lower estimated glomerular filtration rate, higher albuminuria, hypertension, current or former smoking, diabetes, and obesity. In the model-based lifetime projections, the risk of ESRD was highest among persons in the youngest age group, particularly among young blacks. The 15-year observed risks after donation among kidney donors in the United States were 3.5 to 5.3 times as high as the projected risks in the absence of donation. Multiple demographic and health characteristics may be used together to estimate the projected long-term risk of ESRD among living kidney-donor candidates and to inform acceptance criteria for kidney donors. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.)

14 July 2020 in Annals of Internal Medicine
Verified
Journal Article
Closed access
KSKeiichi Sumida
Keiichi Sumida
GNGirish N. Nadkarni
Girish N. Nadkarni
MGMorgan E. Grams
Morgan E. Grams
YSYingying Sang
Yingying Sang
SBShoshana H. Ballew
Shoshana H. Ballew
HHHiddo J.L. Heerspink
Hiddo J.L. Heerspink
Measuring albuminuria is the preferred method for defining and staging chronic kidney disease (CKD), but total urine protein or dipstick protein is often measured instead. This analysis presents eq... Visual Converting Urine PCR to Urine ACR Measuring albuminuria is the preferred method for defining and staging chronic kidney disease (CKD), but total urine protein or dipstick protein is... Background: Although measuring albuminuria is the preferred method for defining and staging chronic kidney disease (CKD), total urine protein or dipstick protein is often measured instead. Objectiv...

1 February 2014 in The American Journal of Clinical Nutrition
Verified
Journal Article
Closed access
ACAlex Chang
Alex Chang
MLMariana Lazo
Mariana Lazo
LALawrence J Appel
Lawrence J Appel
OGOrlando M Gutiérrez
Orlando M Gutiérrez
MGMorgan E Grams
Morgan E Grams
Elevated serum phosphorus is associated with all-cause mortality, but little is known about risk associated with dietary phosphorus intake. We investigated the association between phosphorus intake and mortality in a prospective cohort of healthy US adults (NHANES III; 1998-1994). Study participants were 9686 nonpregnant adults aged 20-80 y without diabetes, cancer, or kidney or cardiovascular disease. Exposure to dietary phosphorus, which was assessed by using a 24-h dietary recall, was expressed as the absolute intake and phosphorus density (phosphorus intake divided by energy intake). All-cause and cardiovascular mortality was assessed through 31 December 2006. Median phosphorus intake was 1166 mg/d (IQR: 823-1610 mg/d); median phosphorus density was 0.58 mg/kcal (0.48-0.70 mg/kcal). Individuals who consumed more phosphorus-dense diets were older, were less often African American, and led healthier lifestyles (smoking, physical activity, and Healthy Eating Index). In analyses adjusted for demographics, cardiovascular risk factors, kidney function, and energy intake, higher phosphorus intake was associated with higher all-cause mortality in individuals who consumed >1400 mg/d [adjusted HR (95% CI): 2.23 (1.09, 4.5) per 1-unit increase in ln(phosphorus intake); P = 0.03]. At 0.35 mg/kcal [adjusted HR (95% CI): 2.27 (1.19, 4.33) per 0.1-mg/kcal increase in phosphorus density; P = 0.01]. At 0.35 mg/kcal; P = 0.01], whereas no association was shown in analyses with phosphorus intake. Results were similar by subgroups of diet quality and in analyses adjusted for sodium and saturated fat intakes. High phosphorus intake is associated with increased mortality in a healthy US population. Because of current patterns in phosphorus consumption in US adults, these findings may have important public health implications.

1 July 2016 in Kidney International
Verified
Journal Article
Closed access
ACAlex Chang
Alex Chang
YCYuan Chen
Yuan Chen
CSChristopher Still
Christopher Still
GWG. Craig Wood
G. Craig Wood
HKH. Lester Kirchner
H. Lester Kirchner
MGMorgan E. Grams
Morgan E. Grams