Trial design

This study was a controlled, randomized clinical trial with an intervention period of 12 weeks (Fig. 1). The trial was registered at the Iranian Registry of Clinical Trials at https://irct.behdasht.gov.ir (Identifier: IRCT20240605062013N1). The design and publication of the study protocol were planned based on the CONSORT 2010 checklist.

Fig. 1

Overview of study timeline. Abbreviations: VAS: visual analogous scale; HHS: Harris Hip Score

Trial population

Participants aged 18 to 60 with pertrochanteric hip fractures admitted to Talaghani Hospital’s orthopedic department will be considered for inclusion. The subjects must satisfy all inclusion criteria and no exclusion criteria presented in Table 1 to be eligible for the trial.

Table 1 The eligibility criteriaSample size calculation

We determined the sample size using Power Analysis & Sample Size Software (PASS) 2021 software (version 21.0.3) for each group with a clinically important difference of 10 points on the change in bone healing (Harris Hip Score) [39], assuming a standard deviation of 10 points. We then used two-sample t-tests, assuming an equal variance of the difference between means, a power of 90%, and a significance level of 5%.

According to the above calculations, 23 people in each group (48 people in total) will be needed. This study will involve 32 people in each group (64 people in total), considering the possibility of 30% dropout and individual non-compliance.

Randomization

‏Randomization in this study will be conducted using the permuted block randomization method. Patients will be randomly assigned to the intervention or placebo group. Randomization was obtained by a computer-based random number generator (https://www.randomizer.org).

‏For random allocation, these conditions will be provided to the respective nurse. It is worth mentioning that patients, researchers, and all medical personnel except for one administering nurse will be blinded to the type of intervention prescribed for the patient (trehalose or placebo).

‏Participation was voluntary, and the participants could quit the study at any time they wanted. The confidentiality of the sample and the data of the participants were guaranteed. The study protocol was registered with the Ethics Committee of Shahid Beheshti University of Medical Sciences.

‏Intervention

Patients who meet the study criteria will be selected to participate in the study. Then, the study topic, objectives, details, and importance of the research will be explained to the patient. These individuals will be reminded that the dosage of tracheal tubes has no serious side effects and is FDA-approved [20]. All expenses will be covered, and at the end of the study, participants will be informed of the test results, or they will be documented in their files. The intervention group will receive 3.3 g of trehalose daily, and the control group will receive 3.3 g of sucrose daily (less than two-thirds of a teaspoon) after breakfast for 12 weeks (received a box containing about 280 g).

The study timetable included the following steps (Table 2).

Table 2 The schedule of enrolment, interventions, and assessments

S0, “Recruitment,” preferably using the list of eligible participants: the assessment of inclusion and exclusion criteria, study questionnaire completion, and obtaining informed consent.

S1, (1 week after S0), “Randomization,” completing the demographic questionnaire, visual analogous scale (VAS), Harris Hip Score (HHS), radiological analysis, and the patient’s dietary intake (PDI), and delivery of trehalose or placebo for 12 weeks.

S2, “Post-allocation: The VAS questionnaire will be completed in weeks 1 and 2. The HHS questionnaire will be completed in weeks 1 and 4.

X-ray Pelvis, including both hips in anteroposterior and lateral views, will be taken in weeks 2 and 4 and will be interpreted based on the RUSH score criteria.

S2, “End of the Study,”: week 12: completing PDI, body mass index (BMI), HHS, and radiological analysis.

S3, “Follow-up,” week 14: contacting and informing the patients regarding the test results.

Blinding

Both participants and data analysts will be blinded in this study. The trehalose supplement and placebo should have the same color, smell, and packaging to provide appropriate blinding. The intervention and control groups will remain unknown to the analyst. Unblinding will take place in the event of unique clinical situations and potentially fatal side effects.

Adherence to the intervention

Adherence to the intervention is checked by phone call and SMS. Also, at the end of the study, the supplement box will be delivered, and the low compliance rate is considered to be less than 80% of the supplement consumption.

Manufacture of study supplements

The trehalose with a chemical formula of C12H22O11•2H2O, purity ≥ 99%, and low metal ion content will be procured from Shaanxi Fruiterco Biotechnology Co., Ltd.

Outcomes

The primary efficacy outcomes of this study are to investigate the effect of trehalose consumption on the following criteria:

(1)

Comparison of bone healing changes in each group and between the two groups.

(2)

Comparison of changes in physical function improvement.

The secondary outcomes of the study are:

(1)

Determination and comparison of pain intensity.

(2)

Determination and comparison of improvements in quality of life.

(3)

Assistance in planning is needed to reduce complications and disease severity.

Anthropometric measurement

At the baseline, anthropometric data, including weight and height, will be measured using a bed scale (Balas company, Iran) and estimated by ulna length (using flexible tape) with an accuracy of 100 g and 0.5 cm, respectively. Finally, the BMI will be determined by dividing weight (kg) by height square (m2). Additionally, patients will be asked to complete a 24-h dietary recall questionnaire at the start and conclusion of the study, which will be analyzed using the Nutritionist-IV (N4) software program (version 7.0; N-Squared Computing, Salem, OR, USA).

Questionnaires and scales

Upon admission, the following socio-demographic data, including age, gender, past medical history, smoking status, and alcohol consumption, will be recorded. The severity of a traumatic injury will be evaluated using the Injury Severity Score (ISS), and the Charlson Comorbidity Index (CCI) will be utilized to estimate medical comorbidities.

To assess pain severity, the visual analog scale (VAS), a numerical and self-reported scale, will be employed. Patients will mark scores on a 10-cm line ranging from 0 to 10, representing “no pain” to “the worst pain ever experienced” [40]. This questionnaire will be completed at the beginning of the intervention, as well as during the first and second weeks.

The evaluation of physical function will be conducted using the Harris Hip Score (HHS), which assesses dimensions including pain, function, range of motion, and the presence of deformity. Scores range from 0 to 100, with higher scores indicating better hip function and less pain [41]. This assessment will be administered at the beginning of the intervention, as well as during the fourth and twelfth weeks.

X-ray imaging of the pelvis, including both hips in anteroposterior and lateral views, will be obtained during the second, fourth, and twelfth weeks of the intervention. The study will include patients with pertrochanteric fractures, which will be categorized and matched across both groups to ensure similarity in fracture types.

Radiological analyses will employ the RUSH Score, a reliable and valid tool specifically designed to evaluate the quality of fracture healing in hip fractures (femoral neck) post-surgery.A trained radiologist, blinded to the group assignments, will evaluate the X-rays based on the RUSH score criteria to ensure an unbiased assessment of bone healing.The RUSH Score includes 10 measures of fracture healing, with each measure being scored as 1, 2, or 3 points. The total score ranges from 10 (indicating no healing) to 30 (indicating complete healing) [42].

Adverse event reporting and management

Flushing, loose feces that self-limit, and momentary bloating are possible signs of mild to moderate gastrointestinal distress. These negative effects are generally indicative of consuming disaccharides. To avoid this, nutritional and clinical conditions will be evaluated regularly, and complete trehalose will not be served in a single meal. One strategy for managing eating intolerance is to temporarily restrict nutritional intake; if acute gastrointestinal issues do not resolve, another strategy is to think about using prokinetic medications [43].

Statistical analysis

Statistical data will be analyzed using SPSS software version 23 (SPSS Inc., Chicago, USA). The Kolmogorov–Smirnov test will be employed to check the normality of each variable. If the data were not normally distributed, a logarithmic transform was applied to normalize them. All normal quantitative data will be expressed as mean ± standard deviation, while qualitative data will be reported as frequency (percentage). For inter-group comparison, the chi-square test will be used for the qualitative data and the independent t-test for the quantitative data. The analysis of covariance (ANCOVA) test will be utilized to compare the means of normal data between the intervention and control groups after adjusting for baseline values and confounding variables (such as age, gender, drug intake, smoking status, alcohol consumption, BMI, marital status, history of comorbidities, education, and energy intake). A paired t-test was applied for intragroup comparison (pre- and post-intervention). Safety analyses are will be conducted based on the intention-to-treat (ITT) dataset. Missing data will be imputed using “regression imputation” method. The significance level was considered at 0.05 for all tests.