A comparison of two pre-race medical screening tools in 5771 running race entrants-SAFER XXVIII.

OBJECTIVE: To determine if two pre-race screening tools (abbreviated tool of two open-ended pre-race medical screening questions [ABBR] vs. a full pre-race medical screening tool [FULL]) identify running race entrants at higher risk for medical encounters (MEs) on race day. METHODS: 5771 consenting race entrants completed both an ABBR and a FULL pre-race screening questionnaire for the 2018 Comrades Marathon (90 km). ABBR tool questions were (1) allergies, and (2) known medical conditions and/or prescription medication use. The FULL tool included multiple domains of questions for chronic diseases including cardiovascular disease (CVD), symptoms, risk factors, allergies and medication use. ABBR responses were manually coded and compared to the FULL tool. The prevalence (%: 95%CI), and the test for equality of prevalence of entrants identified by the ABBR vs. FULL tool is reported. RESULTS: The ABBR identified fewer entrants with allergies (ABBR = 7.9%; FULL = 10.4%: p = 0.0001) and medical conditions/medication use (ABBR = 8.9%; FULL = 27.4%: p = 0.0001). The ABBR tool significantly under-reported entrants with history of cardiovascular disease (CVD), CVD risk factors, other chronic diseases and prescription medication vs. the FULL tool (p = 0.0001). The ABBR tool identified fewer entrants in the "high" (ABBR = 3.4%; FULL = 12.4%) and "very high" risk (ABBR = 0.5%; FULL = 3.4%) categories for race day MEs (p = 0.0001). CONCLUSIONS: An abbreviated pre-race screening tool significantly under-estimates chronic medical conditions, allergies, and race entrants at higher risk for MEs on race day, compared with a full comprehensive screening tool. We recommend that a full pre-race medical screening tool be used to identify race entrants at risk for MEs.

Risk factors associated with gradual onset running-related injuries in 5770 ultramarathon race entrants - SAFER XXXII.

BACKGROUND: There is limited evidence available on contributing factors for gradual onset running-related injuries (GORRIs) in ultramarathon runners. The aim was to determine if selected risk factors were associated with a history of GORRIs in 90-km ultramarathon race entrants. METHODS: Descriptive cross-sectional study. GORRI and medical data using an online pre-race medical screening tool was collected from 5770 consenting race entrants from the 2018 90-km Comrades Marathon. Selected risk factors associated with 12-months history of GORRIs (age, sex, training, chronic diseases and allergies) were analyzed using a multiple model (Poisson regression). Prevalence and prevalence ratios (PR, 95% CIs) are reported. RESULTS: The overall 12-month prevalence of GORRIs was 11.6% (95% CI: 10.8-12.5) and this was higher in females versus males (PR=1.6; 1.4-1.9) (P<0.0001). Novel independent risk factors associated with a history of GORRIs were: history of chronic disease (PR=1.3; P=0.0063); history of allergies (PR=1.7 increased risk for every disease; P<0.0001); fewer training sessions/week (PR=0.8 decreased risk for every two additional training sessions per week; P=0.0005); and increased number of years as a recreational runner (PR=1.1 increased risk per 5 years of running; P=0.0158). CONCLUSIONS: There is a complex interaction between the internal and external risk factors associated with GORRIs in 90-km distance runners. These data can inform injury prevention programs targeted at subgroups of ultradistance runners.

Pre-race self-reported medical conditions and allergies in 133 641 Comrades ultramarathon (90km) runners - SAFER XXIII.

OBJECTIVES: To determine the prevalence of self-reported pre-race chronic medical conditions and allergies in ultramarathon race entrants and to explore if these are associated with an increased risk of race-day medical encounters (MEs). METHODS: Data from two voluntary open-ended pre-race medical screening questions (Q1 - history of allergies; Q2 - history of chronic medical conditions/prescription medication use) were collected in 133641 Comrades Marathon race entrants (2014-2019). Race-day ME data collected prospectively over 6 years are reported as incidence (per 1000 starters) and incidence ratios (IR: 95%CI's). RESULTS: Pre-race medical screening questions identified race entrants with a history of chronic medical conditions and/or prescription medication use (6.9%) and allergies (7.4%). The % entrants with risk factors for cardiovascular disease (CVD) was 30% and being older (>45 years) or male (27.5%) were the most frequent CVD risk factors. 0.3% of entrants reported existing CVD. The overall incidence of MEs was 20/1000 race starters. MEs were significantly higher in race entrants reporting a 'yes' to Q1 (allergies) (IR = 1.3; 1.1-1.5) (p = 0.014) or Q2 (chronic medical conditions and/or prescription medication use) (IR = 1.3; 1.1-1.5) (p = 0.0006). CONCLUSIONS: Voluntary completion of two open-ended questions identified chronic medical conditions and/or prescription medication use in 6.9% and allergies in 7.4% of ultramarathon race entrants. This is lower than that reported for other races that implemented compulsory completion of a more comprehensive pre-screening questionnaire. Despite potential under-reporting, a pre-race self-reported history of chronic medical conditions and allergies was associated with a higher risk of race-day MEs.

Medical Encounters in a 90-km Ultramarathon Running Event: A 6-year Study in 103 131 Race Starters-SAFER XVII.

OBJECTIVE: To determine the incidence and nature of illness-related medical encounters (MEs) at a 90-km, ultramarathon, mass, community-based, endurance running event. DESIGN: Retrospective, descriptive epidemiological study. SETTING: Comrades Marathon (90 km), South Africa. PARTICIPANTS: One lakh three thousand one hundred thirty-one race starters over 6 years (2014-2019). INDEPENDENT VARIABLES: Incidence of moderate and serious/life-threatening MEs. MAIN OUTCOME MEASURES: All MEs were recorded by race medical doctors on race day each year. Medical encounters were recorded by severity, organ system, and final specific diagnosis (2019 consensus statement definition on mass community-based events). Incidences (I: per 1000 starters; 95% confidence intervals) were calculated for MEs. RESULTS: There were 1971 illness-related MEs, with an overall incidence of 19.1 (range, 18.3-20.0). The incidence for serious/life-threatening MEs was 1.8 (range, 1.6-2.1). Incidences of MEs by organ systems affected were as follows: fluid/electrolyte (8.8; 8.3-9.4), central nervous system (4.0; 3.7-4.5), and gastrointestinal system (2.9; 2.6-3.2). Dehydration (I = 7.5: 7.0-8.1) and exercise-associated muscle cramping (I = 3.2: 2.9-3.6) were the 2 most common specific diagnoses. CONCLUSION: The incidence of MEs in the 90-km Comrades Marathon was one of the highest incidences of MEs reported in an endurance running event (1 in 52 starters and 1 in 556 starters for serious/life-threatening MEs). Preventative measures to reduce MEs are needed, and further investigations into the risk factors associated with MEs could assist in managing the risk and better prepare athletes, race organizers, and medical directors.

Avoid adding insult to injury - correct management of sick female endurance athletes.

OBJECTIVES: To evaluate the efficacy of Ringer's lactate, isotonic saline and hypertonic saline on the clinical and biochemical recovery of athletes with exercise-associated hyponatraemic encephalopathy caused by fluid overload. METHODS: We retrospectively reviewed serial blood sodium concentrations (Na+) and qualitative signs of recovery and time to recovery in two healthy menstruant females hospitalised with dilutional exercise-associated hyponatraemic encephalopathy after withdrawal from the 2011 Comrades Marathon (89 km) and Argus Cycle Tour (109 km). RESULTS: Improvements in blood Na+ did not occur with intravenous administration of Ringer's lactate solution, but did occur with administration of isotonic and hypertonic saline. Qualitative improvements in mental status were not quantitatively related to the biochemical value of blood Na+ or subsequent return to normonatraemia. CONCLUSIONS; Hyponatraemia should be suspected in all female athletes presenting to the medical area of endurance races with vomiting, altered mental status and a history of high fluid intake. If a diagnosis of exercise-associated hyponatraemia with cerebral encephalopathy is confirmed, the treatment of choice is administration of an intravenous bolus of hypertonic saline. Administration of Ringer's lactate should be discouraged, as this does not correct Na+ and appears to delay recovery.

Acute renal failure in four Comrades Marathon runners ingesting the same electrolyte supplement: coincidence or causation?

OBJECTIVES: To evaluate common factors associated in the development of acute renal failure (ARF) in Comrades Marathon runners. METHODS: This was a retrospective case series of 4 runners hospitalised post-race with ARF in the 89 km 2010 Comrades Marathon. The outcome measures were incidence of analgesic use, levels of creatine phosphokinase (CPK) and degree of electrolyte supplementation (sodium, potassium, calcium and magnesium). RESULTS: The incidence of ARF was 1/4 125 runners. They presented with rhabdomyolysis (mean admission CPK of 36 294 IU) and hyponatraemia (mean admission blood sodium level of 133 mEq/l). All had ingested an analgesic during the run (3 ingested a non-steroidal anti-inflammatory drug) and the same readily available anti-cramp electrolyte supplement. The average amount of supplemental sodium (452 mg), potassium (393 mg), calcium (330 mg) and magnesium (154 mg) ingested via this particular electrolyte supplement before and during the run did not exceed the recommended upper limits of daily intake. Three of the runners were Comrades Marathon novices. CONCLUSIONS: There is a continuing need to clarify the specific cluster variants that cause ARF in Comrades Marathon runners, as the risk factors appear to have evolved since the first case described over 40 years ago.

Hypernatremia and intravenous fluid resuscitation in collapsed ultramarathon runners.

OBJECTIVE: To determine if a return to normonatremia is required for symptomatology to resolve in collapsed hypernatremic runners and if intravenous (IV) administration of an isotonic solution would adversely affect serum sodium concentration ([Na+]) in collapsed normonatremic runners. DESIGN: Observational study. SETTING: 2006 Comrades Marathon. PARTICIPANTS: 103 collapsed runners. MAIN OUTCOME MEASURE: Final serum [Na] upon discharge. RESULTS: 58% of all collapsed runners were hypernatremic. Hypernatremic runners reported significantly more vomiting than normonatremic runners (79 versus 34%; P < 0.001). A significant decrease in serum [Na] in hypernatremic collapsed runners occurred after the IV administration of either 1 L of 0.45% normal saline (150.5 +/- 3.5 versus 148.0 +/- 4.6; P < 0.05) or Ringers lactate solution (147.7 +/- 2.2 versus 146.2 +/- 2.1; P < 0.05). One liter of IV fluid administration caused an increase in plasma volume that was not significantly different between (1) hypernatremic runners receiving a hypotonic solution (13.5 +/- 12.7%) and (2) normonatremic runners receiving an isotonic solution (15.6 +/- 11.3%). The final serum [Na+] of hypernatremic runners was above the range for normonatremia upon discharge (>145 mmol/L). CONCLUSIONS: A return to normonatremia was not required for hypernatremic runners to "recover" and be discharged from the medical tent. Vomiting either aggravated and/or facilitated the development of hypernatremia. IV administration of 1 L of either (1) a hypotonic solution to hypernatremic runners or (2) an isotonic solution to both normonatremic and hypernatremic runners did not produce any adverse biochemical or cardiovascular changes and can therefore be considered a safe and effective treatment for collapsed runners if used in this context.

Dysnatremia predicts a delayed recovery in collapsed ultramarathon runners.

OBJECTIVE: To assess (1) the incidence of dysnatremia in collapsed runners presenting to the medical tent of the 89-km Comrades Marathon and whether dysnatremia influences time to discharge, and (2) whether intravenous fluids could restore serum sodium concentration ([Na+]) to 140 mM faster than could the administration of oral fluids. DESIGN: Prospective randomized controlled trial. SETTING: 2005 Comrades Marathon. PARTICIPANTS: One hundred thirty-three collapsed runners and 31 control-group runners. INTERVENTIONS: Collapsed runners presenting to the medical tent at the finish of the 2005 Comrades Marathon were randomized into an intravenous or oral fluid administration group, with the type and amount of fluid administered dictated by initial [Na+]. MAIN OUTCOME MEASURES: Time to discharge, serum [Na+]. RESULTS: Forty-five percent of collapsed runners were hypernatremic, 2% were hyponatremic, and 53% were normonatremic. Normonatremic runners spent significantly less time in the medical tent (80 +/- 31 minutes) compared with hypernatremic (102 +/- 36 minutes) and hyponatremic (146 +/- 122 minutes) runners. Intravenous fluid therapy produced larger but nonsignificant reductions in [Na+] than oral therapy (-2.1 +/- 3.1 versus -0.7 +/- 1.8 mM); however, 45% of runners assigned to the oral fluid group could not tolerate oral rehydration. CONCLUSIONS: A slight majority of collapsed runners were normonatremic and spent significantly less time in the medical tent compared with hyper- and hyponatremic athletes. Initial rates of correction of hypernatremia were similar with intravenous and oral hypotonic fluid therapy. Clinicians should be advised that intravenous fluid resuscitation may best benefit hypernatremic collapsed runners who are intolerant to oral fluid ingestion.