Short summary

Constipation increases the risk for postoperative complication. In clinical practice, there is a considerable variation in pharmacologic post-operative treatment of constipation. There is limited research on the use of laxatives in this field and it is thus uncertain which laxative is the best choice after hip fracture surgery. The aim of this study is to investigate which constipation therapy is the most optimal choice for postoperative treatment in elderly after hip fracture surgery.

Rationale

Acute constipation is a common adverse event following surgery and is related to immobility, decreased fluid intake, low intake of fiber and use of opioid in connection to the surgery. A Danish observational study found that following hip fracture nearly 70% developed constipation during first postoperative days. Constipation cause discomfort and decreased life quality in patients and if constipation is prolonged in can lead to serious complication such as exacerbation of post-operative ileus, intestinal obstruction and severe pain. Complications can prolong hospital stay, increase health cost and nursing care time and effective prevention is considered to be an important part of care following hip surgery.

Despite the wide use of laxatives for post-operative constipation, no randomized controlled studies have investigated postoperative use of laxatives following hip surgery and only a few small studies have been performed for other types of surgery indicating a possible effect of macrogol, magnesium oxide, senna and docusate but data is to sparse for allowing recommendation for a specific laxative regimen.

A Danish reference programme of hip fracture surgery do not state any recommendation for post-operative treatment of constipation and as a result there is a considerably variation in management of postoperative constipation following orthopedic surgery in Denmark. Use of laxatives appears to be based on consensus among experts or taken for recommendations for laxative use with opioids-induced constipation in oncology or palliative care or acute or chronic constipation. The recommendations for these conditions are in general are osmotic laxatives such as lactulose, macrogol or magnesium oxide as first line treatment and if the effect is insufficiently, treatment should be change to a stimulant laxative such as bisacodyl or sodium picosulfate or a combination of stimulating and osmotic laxatives. Even for these conditions evidence from well-designed RCT studies of routine preventive laxative is sparse but macrogol has in general been better investigated than lactulose and most comparative data from chronic constipation suggest similar efficacy, but with lower incidence of vomiting and flatulence associated with macrogol compared to lactulose. Magnesium oxide has only been very sparsely investigated despite being very frequently used in Denmark through many years. A reason for post-operative constipation is use of opioids. When used in palliative care small studies indicate that type of opioids, dose or administrations form do not have an influence on the severity of constipation. The use of laxative is not based on evidence on effectiveness as only very little research has been done in this field and accordingly it is uncertain which laxative is the best choice after hip fracture surgery.

The aim of this double-blinded randomized controlled study is to investigate whether there is a clinically relevant effect of two laxative regimens after hip fracture surgery compared to placebo.

Description of the cohort

Hip fracture patients, age ≥ 65 years admitted through the Emergency Department (FAM) or suffer an acute hip fracture during their hospitalization and need surgery. The patients are included from six orthopedic surgery departments around Denmark. To be included, the patient must speak and understand Danish and be able to give informed consent independently.

Data and biological material

Diagnosis codes, data on length of hospital stay and readmission is obtained from The Danish National Patient Register.

Collaborating researchers and departments

Department of Orthopedic Surgery, Odense University Hospital (Odense Hospital and Svendborg Hospital)

• M.D. Ph.D, Bjarke Viberg

Department of Orthopedic Surgery, Lillebaelt Hospital (Kolding Hospital)

• M.D. Ph.D, Ane Simony

Department of Orthopedic Surgery, Sønderjylland Hospital (Aabenraa Hospital)

• M.D. Ph.D, Jesper Ougaard Schønnemann

Department of Orthopedic Surgery, Region Zealand University Hospital (Køge Hospital)

• M.D. Ph.D, Erling Laxafoss

Department of Orthopedic Surgery, Region Zealand University Hospital (Holbaek Hospital)

• M.D. Lasse Danborg

Institute of Clinical Research, University of Southern Denmark

• M.D, Ph.d, DMSc., Per Damkier

Department at Hospital Pharmacy Funen, Odense University Hospital

• M.S. (Pharm), PhD, DMSc., Anton Pottegård