Yu Hui Chiu

Effects of 100-km ultramarathon on acute kidney injury

Objective:To evaluate the prevalence and characteristics of acute kidney injury (AKI) in 100-km ultramarathon runners. Design:Prospective observational study. Setting:The 2011 Soochow University ultramarathon, in which each athlete ran for 100 km. Participants:All Taiwanese entrants who participated in the 100-km race and lived in the northern part of Taiwan were invited to participate in the study. Main Outcome Measures:Acute kidney injury was defined using the Acute Kidney Injury Network criteria. Blood and urine samples were collected 1 week before, immediately after, and 1 day after the race. Results:Immediately after the race, 85% (22) of the 26 subjects were diagnosed with AKI, 65% (16) with moderate dehydration, 23% (6) with muscle cramps, and 12% (3) with hematuria. Body weight was significantly decreased from prerace to all postrace measurements. Plasma levels of potassium ion, creatinine, renin, and aldosterone were significantly elevated immediately after the race and then significantly reduced 1 day after the race. Changes in plasma levels of sodium, creatine kinase, and creatine kinase–MB, as well as urine potassium and creatinine, were indicative of AKI. Conclusions:Transient AKI and muscle cramps are very common in 100-km ultramarathon runners. All transient ultra-runners who developed AKI in this study recovered their renal function 1 day later. Clinical Relevance:Ultramarathon running is associated with a wide range of significant changes in hematological parameters, several of which can be associated with potentially serious renal and physiological abnormalities.

Risk factors for acute kidney injury in the elderly undergoing contrast-enhanced computed tomography in the emergency department

Background: There have been few studies focusing on the incidence and risk factors for elderly patients undergoing computed tomography (CT) scans with intravascular contrast medium, who develop contrast‐induced nephropathy (CIN) in the emergency department (ED). Our objective was to investigate the incidence of and risk factors for, CIN in elderly patients seen in the ED, who receive intravenous contrast media for CT examination. Methods: Patients ≥65 years of age who received contrast‐enhanced CT were eligible for inclusion in this retrospective analysis. CIN was defined as an increase in serum creatinine (sCr) ≥0.5 mg/dL 48 to 72 hours after intravenous contrast administration. Multiple logistic regression analysis for risk factors for CIN and Chi‐square test were performed for trend analysis for CIN incidence and mortality of different risk scores. Results: A total of 594 patients, with a mean age of 79.8 ± 6.8 years were included. The overall incidence of CIN was 8.6%. In multivariate analyses, CIN was associated with diabetes mellitus [adjusted odds ratio (OR) = 1.93; 95% confidence interval (CI) = 1.04–3.62], precontrast sCr >1.5 mg/dL (OR = 2.72; 95% CI = 1.44–5.13), and acute hypotension (OR = 3.56; 95% CI = 1.29–9.84). CIN and mortality increased with increasing risk score (p < 0.001 and p = 0.001, respectively). The all‐cause in‐hospital mortality rate was 13.1%, and the mortality rates for patients with and without CIN (p < 0.001) were 47.1% and 9.9%, respectively. Conclusion: Our investigation confirmed diabetes mellitus, precontrast sCr >1.5 mg/dL and acute hypotension as risk factors for CIN, and also developed a simple risk score for elderly patients seen in the ED.

Early changes of the anemia phenomenon in male 100-km ultramarathoners

Background Sports anemia is a widely observed phenomenon after prolonged running. There are various factors that contribute to sports anemia, including hemodilution, exercise‐induced oxidative stress, iron deficiency, gastrointestinal bleeding, hematuria, and hemolysis resulting from foot‐strike and/or from compression of contracting muscles on capillaries. Until now, there has been no published report that describes the overall hematological, urinary, and fecal consequences in Asian male ultramarathoners after a 100‐km (62.5‐mile) ultramarathon event. Methods A total of 25 male runners were recruited into our study. Blood was drawn 1 week before, immediately after, and then 24 hours subsequent to the race. Hematological samples were analyzed for the anemia phenomenon. Additionally, urinary and fecal samples were collected before and after the race for detection of occult blood. Results The blood hemoglobin and erythropoietin values of the recruited runners showed a statistically significant rise in the immediate post‐race values and a rapid drop in values at 24 hours post‐race. Blood concentrations of red blood cells and hematocrit were significantly lower at 24 hours post‐race compared with pre‐race. The white blood cell count, interleukin‐6, tumor necrosis factor‐alpha, high‐sensitivity C‐reactive protein, and ferritin all showed significant increases both immediately after and 24 hours post‐race compared with pre‐race hematological values. There were immediate decreases of both haptoglobin and iron, as well as an increase of total iron‐binding capacity levels in post‐race blood tests. For both urinary and fecal samples, there was a statistically significant difference between the pre‐ and post‐race results in occult blood. Conclusion Running a 100‐km ultramarathon will induce substantial sports anemia, and oxidative stress response, hemolysis, hematuria, and gastrointestinal bleeding are typical factors that contribute to its onset.

Influence of a 100-km ultra-marathon on hepatitis B carrier runners.

This study compares the serological markers between runners who are hepatitis B virus carries (HBVc) and runners who are non-HBVc in a 100-km ultra-marathon race. Blood samples of 8 HBVc and 18 non-HBVc runners were drawn 1 week before, immediately following, and 24 h after the race. Samples were analyzed and compared between the 2 groups for liver function tests, muscle damage markers and oxidative stress cytokines. For HBVc runners, HBV-DNA (hepatitis B virus-deoxyribonucleic acid) levels were also evaluated for virus reactivation. The results demonstrate a statistically significant increase in both immediate and 24-h post-race values for alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK), high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), compared with pre-race values. No statistically significant difference was observed between the 2 groups for the values of AST, LDH, CK, hs-CRP, IL-6 and TNF-α either before or after the race. There was also no statistically significant change in the levels of HBV-DNA in HBVc runners. These findings suggest that HBVc runners do not have higher risks of liver function impairment, muscle breakdown and inflammatory response compared to non-HBVc runners in such endurance races.

Whether intravenous contrast is necessary for CT diagnosis of acute appendicitis in adult ED patients

RATIONALE AND OBJECTIVES To assess the necessity of intravenous contrast medium for abdominopelvic computed tomography (CT) diagnosis of acute appendicitis (APP) among adult patients with right lower quadrant (RLQ) abdominal pain at emergency department (ED). MATERIALS AND METHODS ED patients with clinical suspicion of APP from RLQ pain for a period of 8 months were enrolled retrospectively. Both pre- and postintravenous contrast-enhanced CT scans were performed for these patients. The visibility of vermiform appendix and specific CT findings of APP were recorded separately for noncontrast CT (NCT) and contrast-enhanced CT (CCT) images without knowledge of the patients identity and final diagnosis. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CT diagnosis for APP were compared between the two groups. The ease of identifying appendix was also compared. RESULTS Forty-two (42.0%) of the 100 patients (55 males, 45 females; age range, 16-90 years; mean age, 49.3 years) were APP. There was no significant difference for the visibility of appendix (94% vs. 91%; P = .589) and radiological characters between the CCT and NCT groups. There were significant differences between the two groups for sensitivity (100% vs. 90.5%; P = .036), specificity (94.8% vs. 100%; P = .038), PPV (93.3% vs. 100%; P = .021), NPV (100% vs. 93.5%; P = .021), but no significant difference for accuracy (97% vs. 96%; P = 1). The appendix was easier to detect on CCT than NCT images (P = .013). CONCLUSION The diagnostic sensitivity of CCT was significantly better than that of NCT. Intravenous contrast administration could also make doctors easier in indentifying appendixes.

Different duration of high-altitude pre-exposure associated with the incidence of acute mountain sickness on Jade Mountain

OBJECTIVE The objective of this study is to determine the association between the duration of high-altitude (>3000 m) pre-exposure and acute mountain sickness (AMS) incidence. METHODS A prospective observational study was conducted on 2 random days each month from April 2007 to March 2008 at Paiyun Lodge (3402 m), Jade Mountain, Taiwan. Demographic data, prior AMS history, symptoms, and scores and the days and times of high-altitude pre-exposure within the preceding 2 months were obtained from lowland (<1500 m) trekkers. RESULTS Totally, 1010 questionnaires were analyzed; 106, 76, and 828 trekkers had pre-exposure lasting at least 3 days (group 1), less than 3 days (group 2), and 0 days (group 3), respectively. Acute mountain sickness incidence was significantly higher in groups 2 and 3 than in group 1 (21.70%, 35.53%, 37.08%, respectively; P = .008). Logistic regression analysis indicated a significantly lower AMS risk in group 1 (group 1, P = .004; odds ratio [OR], 0.479; 95% confidence interval [CI], 0.290-0.791; group 2, P = .226; OR, 0.725; 95% CI, 0.430-1.221). In group 1, 28 and 78 trekkers had single and intermittent multiple pre-exposure, respectively. There was no difference in the incidence or severity of AMS symptoms between single and intermittent multiple pre-exposure (AMS, P = .838; headache, P = .891; dizziness or lightheadedness, P = .414; fatigue and/or weakness, P = .957; gastrointestinal symptoms, P = .257; difficulty sleeping, P = .804; AMS score, P = .796). CONCLUSIONS High-altitude pre-exposure lasting at least 3 days within the preceding 2 months was associated with a significant lower AMS incidence during a subsequent ascent among Jade Mountain trekkers.

Clinical Impact of Speed Variability to Identify Ultramarathon Runners at Risk for Acute Kidney Injury.

Background Ultramarathon is a high endurance exercise associated with a wide range of exercise-related problems, such as acute kidney injury (AKI). Early recognition of individuals at risk of AKI during ultramarathon event is critical for implementing preventative strategies. Objectives To investigate the impact of speed variability to identify the exercise-related acute kidney injury anticipatively in ultramarathon event. Methods This is a prospective, observational study using data from a 100 km ultramarathon in Taipei, Taiwan. The distance of entire ultramarathon race was divided into 10 splits. The mean and variability of speed, which was determined by the coefficient of variation (CV) in each 10 km-split (25 laps of 400 m oval track) were calculated for enrolled runners. Baseline characteristics and biochemical data were collected completely 1 week before, immediately post-race, and one day after race. The main outcome was the development of AKI, defined as Stage II or III according to the Acute Kidney Injury Network (AKIN) criteria. Multivariate analysis was performed to determine the independent association between variables and AKI development. Results 26 ultramarathon runners were analyzed in the study. The overall incidence of AKI (in all Stages) was 84.6% (22 in 26 runners). Among these 22 runners, 18 runners were determined as Stage I, 4 runners (15.4%) were determined as Stage II, and none was in Stage III. The covariates of BMI (25.22 ± 2.02 vs. 22.55 ± 1.96, p = 0.02), uric acid (6.88 ± 1.47 vs. 5.62 ± 0.86, p = 0.024), and CV of speed in specific 10-km splits (from secondary 10 km-split (10th – 20th km-split) to 60th – 70th km-split) were significantly different between runners with or without AKI (Stage II) in univariate analysis and showed discrimination ability in ROC curve. In the following multivariate analysis, only CV of speed in 40th – 50th km-split continued to show a significant association to the development of AKI (Stage II) (p = 0.032). Conclusions The development of exercise-related AKI was not infrequent in the ultramarathon runners. Because not all runners can routinely receive laboratory studies after race, variability of running speed (CV of speed) may offer a timely and efficient tool to identify AKI early during the competition, and used as a surrogate screening tool, at-risk runners can be identified and enrolled into prevention trials, such as adequate fluid management and avoidance of further NSAID use.

Rate of ascent and acute mountain sickness at high altitude.

Objective:To examine the effect of ascent rate on the induction of acute mountain sickness (AMS) in young adults during a climb to Jiaming Lake (3350 m) in Taiwan. Design:Prospective, nonrandomized. Setting:Climb from 2370 to 3350 m. Participants:Young adults (aged 18 to 26 years) (N = 91) chose to participate in either the fast ascent (3 days; n = 43) or slow ascent (4 days; n = 48) group (1 and 2). Assessment of Risk Factors:Two criteria were used to define AMS. A Lake Louise score ≥3 and Lake Louise criteria [in the setting of a recent gain in altitude, the presence of headache and at least 1 of gastrointestinal discomfort (anorexia, nausea, or vomiting), fatigue or weakness, dizziness or lightheadedness, or difficulty sleeping]. Main Outcome Measures:Heart rate, blood oxygen saturation (SaO2), and symptoms of AMS were monitored each morning and evening. Results:Baseline characteristics were similar between groups, except for significant differences in history of alcohol consumption (P = 0.009) and climbing experience above 3000 m (P < 0.001). The incidence of AMS was not associated with the rate of ascent. Acute mountain sickness was most prevalent in group 1 on day 2 in the evening and in group 2 on day 3 in the evening. In both groups, AMS correlated with the initial reduction in SaO2. Body mass index (BMI) >24 kg/m2 was identified as a significant risk factor for AMS. Conclusions:The development of AMS was closely associated with an initial reduction in SaO2. A BMI >24 kg/m2 also contributed to the occurrence of AMS. Clinical Relevance:These findings indicate that factors other than ascent rate should be considered when trying to ameliorate the risk of AMS.

The impact of hepatitis B carrier on cardiac troponin I in 100-km ultramarathon runners

Background Prolonged endurance exercise is known to cause elevation of cardiac troponin I (cTnI). Previous studies have reported the correlation of several factors with exercise‐induced cTnI release. However, the investigation of the predictors for elevated cTnI and postrace kinetics of cTnI after ultramarathon running is lacking, especially in an Oriental population. Methods Twenty‐six participants, including eight hepatitis B virus carrier (HBVc) runners, who finished a 100‐km ultramarathon in Taiwan were enrolled. For each participant, blood samples were collected 1 week before the race, as well as immediately and 24 hours after the finish. Results The results showed that 19 runners (73.1%) had postrace elevated cTnI levels and eight (30.8%) had elevated cTnI values lasting more than 24 hours after the run. A multiple linear regression analysis demonstrated that the HBV status was a factor related to the high level of cTnI after 24 hours of running (&bgr; = 0.03, p = 0.08). The recovery of plasma cTnI levels was delayed in ultramarathon runners with latent HBV infection. Among HBVc runners, multiple linear regression analyses showed age (&bgr; = −0.01), previous running experience (&bgr; = −0.06), training distance (&bgr; = 0.37), and 4 hours of running distance (&bgr; = −0.04) as significant predictors of higher postrace cTnI levels. Conclusion For most athletes, cTnI values significantly increased immediately following the race in the absence of adverse clinical sequelae, and HBVc runners had higher and prolonged cTnI levels. While several factors are identified for such HBV effects, the specific causes need further elucidation.

The changes of red blood cell viscoelasticity and sports anemia in male 24-hr ultra-marathoners

Background: In endurance sports, stress, dehydration and release of chemical factors have been associated with red blood cell (RBC) alterations of structure and function, which may contribute to sports anemia, a well‐observed phenomenon during long‐distance running. Until now, the investigation of the changes of viscoelastic properties of RBC membrane, a decisive factor of RBC deformability to avoid hemolysis, is lacking, especially in an Oriental population. Methods: nineteen runners were prospectively recruited into our study. Hematological parameters were analyzed before and immediately after the 2015 Taipei 24H Ultra‐Marathon Festival, Taiwan. Video particle tracking microrheology was used to determine viscoelastic properties of each RBC sample by calculating the dynamic elastic modulus G′(f) and the viscous modulus G″(f) at frequency f = 20 Hz. Results: Haptoglobin, RBC count, hemoglobin, hematocrit, mean cell hemoglobin, plasma free hemoglobin and unsaturated iron‐binding capacity values of the recruited runners showed a statistically significant drop in the post‐race values. Blood concentration of reticulocyte and ferritin were significantly higher at post‐race compared with pre‐race. 15 out of the 19 runners had a concurrent change in the elastic and the viscous moduli of their RBCs. Changes in the elastic and the viscous moduli were correlated with changes in the RBC count, hemoglobin and hematocrit. Conclusion: Viscoelasticity properties, the elastic modulus G′(f) and the viscous modulus G″(f) of RBCs are associated with endurance exercise‐induced anemia.