METHODS AND ANALYSIS: Hip fracture Accelerated surgical TreaTment And Care tracK (HIP ATTACK) is a multicentre, international, parallel-group randomised controlled trial (RCT). Patients who suffer a hip fracture are randomly allocated to either accelerated medical assessment and surgical repair with a goal of surgery within 6 hours of diagnosis or standard care where a repair typically occurs 24 to 48 hours after diagnosis. The primary outcome of this substudy is the development of AKI within 7 days of randomisation. We anticipate at least 1998 patients will participate in this substudy.

ETHICS AND DISSEMINATION: We obtained ethics approval for additional serum creatinine recordings in consecutive patients enrolled at 70 participating centres. All patients provide consent before randomisation. We anticipate reporting substudy results by 2021.

METHODS: Prospective cohort study of Spanish patients nested in the HIP ATTACK-1 trial. The HIP ATTACK-1 was an international, randomized, controlled trial (17 countries, 69 hospitals, 7 in Spain, highest recruiting country). Patients were randomized to either accelerated surgery (goal of surgery within 6 h of diagnosis) or standard care. Participants were ≥45 years of age who presented with a low-energy hip fracture requiring surgery.

RESULTS: Among 534 patients in the Spanish cohort, 69 (12.9 %) patients died at 90 days follow-up, compared to 225 (9.2 %) in the non-Spanish cohort (p = 0.009), mostly due to higher nonvascular related mortality. A composite of major postoperative complication occurred in 126 patients (23.6 %). The most common perioperative complications were myocardial injury (189 patients, 35.4 %), infection with no sepsis (86 patients, 16.1 %) and perioperative delirium (84 patients, 15.7 %); all these complication rates in Spain were significantly higher than the non-Spanish patients (29.2 % p = 0.005; 11.9 % p = 0.008 and 9.2 % p < 0.0001, respectively). Spanish cohort patients were older and had more comorbidities than the non-Spanish cohort, evidencing their greater frailty at baseline. Among Spanish patients, the median time from hip fracture diagnosis to surgery was 30.0 h (IQR 21.1-53.9) in the standard-care group, with 68.8 % of patients receiving surgery within 48 h of diagnosis. This median time was lower in the non-Spanish cohort (22.8 h, IQR 9.5-37.0), where 82.1 % of patients were operated within 48 h.

CONCLUSIONS: In the HIP ATTACK-1 trial, 1 in 8 patients died 90 days after a hip fracture in Spain. The most common complication after a hip fracture was myocardial injury, followed by infection and delirium. Spanish patients had worse outcomes than non-Spanish patients. Research needs to focus on new interventions such as accelerated surgery and perioperative troponin measurement with the appropriate investment of resources, to prevent and identify early these complications with a goal of improving mortality for this high-risk population.

METHODS AND ANALYSIS: HIP ATTACK is a multicentre, international, parallel group randomised controlled trial (RCT) that will include patients ≥45 years of age and diagnosed with a hip fracture from a low-energy mechanism requiring surgery. Patients are randomised to accelerated medical assessment and surgical repair (goal within 6 h) or standard care. The co-primary outcomes are (1) all-cause mortality and (2) a composite of major perioperative complications (ie, mortality and non-fatal myocardial infarction, pulmonary embolism, pneumonia, sepsis, stroke, and life-threatening and major bleeding) at 90 days after randomisation. All patients will be followed up for a period of 1 year. We will enrol 3000 patients.

ETHICS AND DISSEMINATION: All centres had ethics approval before randomising patients. Written informed consent is required for all patients before randomisation. HIP ATTACK is the first large international trial designed to examine whether accelerated surgery can improve outcomes in patients with a hip fracture. The dissemination plan includes publishing the results in a policy-influencing journal, conference presentations, engagement of influential medical organisations, and providing public awareness through multimedia resources.

METHODS: The HIP fracture Accelerated surgical TreaTment And Care tracK (HIP ATTACK) trial was a randomized controlled trial designed to determine whether accelerated surgery for hip fracture was superior to standard care in reducing death or major complications. This substudy is a post-hoc analysis of 1392 patients (from the original study of 2970 patients) who had a cardiac biomarker/enzyme measurement (>99.9% had a troponin measurement and thus "troponin" is the term used throughout the paper) at hospital arrival. The primary outcome was all-cause mortality. The secondary composite outcome included all-cause mortality and non-fatal myocardial infarction, stroke, and congestive heart failure 90 days after randomization.

RESULTS: Three hundred and twenty-two (23%) of the 1392 patients had troponin elevation at hospital arrival. Among the patients with troponin elevation, the median time from hip fracture diagnosis to surgery was 6 hours (interquartile range [IQR] = 5 to 13) in the accelerated surgery group and 29 hours (IQR = 19 to 52) in the standard care group. Patients with troponin elevation had a lower risk of mortality with accelerated surgery compared with standard care (17 [10%] of 163 versus 36 [23%] of 159; hazard ratio [HR] = 0.43 [95% confidence interval (CI) = 0.24 to 0.77]) and a lower risk of the secondary composite outcome (23 [14%] of 163 versus 47 [30%] of 159; HR = 0.43 [95% CI = 0.26 to 0.72]).

CONCLUSIONS: One in 5 patients with a hip fracture presented with myocardial injury. Accelerated surgery resulted in a lower mortality risk than standard care for these patients; however, these findings need to be confirmed.