Association Between Body Mass Index and Acute Postoperative Pain Following Laparoscopic Cholecystectomy: A Retrospective Clinical Study

Summary

This retrospective study shows that higher body mass index is independently associated with greater acute postoperative pain intensity and increased opioid requirements after laparoscopic cholecystectomy, supporting BMI-informed perioperative pain assessment and individualized analgesic planning.

Abstract

Obesity has been increasingly recognized as a factor associated with altered pain perception and postoperative analgesic requirements; however, its relationship with acute postoperative pain following laparoscopic cholecystectomy remains incompletely defined. This retrospective observational study investigated the association between body mass index (BMI) and acute postoperative pain severity in adult patients undergoing elective laparoscopic cholecystectomy. Ninety-six patients were categorized into obese and non-obese groups according to BMI criteria for Chinese adults. Demographic characteristics, perioperative variables, postoperative numeric rating scale (NRS) pain scores at multiple time points, and opioid consumption converted to oral morphine equivalents (OME) were collected from medical records. Multivariable logistic regression was used to evaluate the association between BMI and moderate-to-severe postoperative pain, defined as a 24 h mean NRS score ≥4. Compared with non-obese patients, obese patients had higher NRS scores at 6 h, 12 h, and 24 h after surgery, higher first NRS scores in the post-anesthesia care unit, and greater postoperative opioid consumption. In the adjusted regression model, continuous BMI was independently associated with moderate-to-severe postoperative pain after adjustment for age, sex, American Society of Anesthesiologists classification, and intraoperative opioid consumption. These findings suggest that elevated BMI is associated with greater acute postoperative pain severity and analgesic requirements after laparoscopic cholecystectomy. BMI-informed perioperative risk assessment may help guide individualized postoperative pain management in this patient population.

Introduction

Laparoscopic cholecystectomy (LC) is one of the most widely performed minimally invasive abdominal procedures and is generally associated with less tissue trauma and faster recovery than open surgery. Nevertheless, clinically relevant acute postoperative pain may still occur after LC, and insufficient analgesia can delay mobilization, increase opioid exposure, and reduce patient satisfaction. Current postoperative pain management increasingly emphasizes procedure-specific assessment, multimodal analgesia, and opioid stewardship rather than uniform opioid-based regimens for all patients^1,2.

Protocol

This retrospective observational study was approved by the Ethics Committee of Anji County Hospital of Traditional Chinese Medicine (approval No. 2025-13). The requirement for written informed consent was waived by the Ethics Committee because this study used de-identified retrospective clinical data and involved no additional patient intervention. This study was reported in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guideline, and the completed STROBE checklist is provided as Supplementary File 1. The reagents, equipment, and software used are listed in the Table of Mater....

Results

Patient screening and baseline characteristics

A total of 132 patients who underwent elective laparoscopic cholecystectomy during the study period were initially screened and assessed for eligibility. Among them, 36 patients were excluded, including 6 patients aged <18 or >65 years, 5 patients with ASA physical status ≥III, 7 patients with chronic pain or long-term use of analgesics, sedatives, antidepressants, or anxiolytics, 2 patients with a history of opioid or alcoh.......

Discussion

This retrospective observational study found that BMI was independently associated with acute postoperative pain severity after laparoscopic cholecystectomy. Compared with non-obese patients, obese patients had higher resting NRS scores at 6 h, 12 h, and 24 h after surgery, a higher 24 h mean NRS score, and greater postoperative opioid consumption expressed as OME.

In the adjusted logistic regression model, each 1 kg/m² increase in BMI was associated with higher odds of moderate-to-.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Anesthesia information system	Anji County Hospital of Traditional Chinese Medicine	Institutional anesthesia information system	Used to extract anesthesia duration, operative duration, intraoperative opioid administration, intraoperative monitoring records, and anesthesia-related timestamps.
Anesthesia workstation	Dräger	Fabius plus XL	Representative anesthesia workstation used for delivery and maintenance of general anesthesia with tracheal intubation.
Bispectral index monitor	Medtronic	BIS Vista Monitor 186-1046; BIS Quatro sensor 186-0106	Used when available for depth-of-anesthesia monitoring and adjustment of anesthetic depth according to institutional practice.
Cisatracurium besylate injection	Jiangsu Hengrui Pharmaceuticals Co., Ltd.	China NMPA approval No. H20060869	Nondepolarizing neuromuscular blocking agent used to facilitate tracheal intubation when selected by the attending anesthesiologist.
Electronic medical record (EMR) system	Anji County Hospital of Traditional Chinese Medicine	Institutional EMR/HIS system	Used to extract demographic data, height, body weight, BMI, ASA physical status, admission/discharge records, length of hospital stay, medication orders, and other clinical variables.
Endotracheal tube	Medtronic / Shiley	Shiley cuffed oral/nasal tracheal tube, adult sizes	Representative airway device used for tracheal intubation during general anesthesia.
Fentanyl citrate injection	Jiangsu Nhwa Pharmaceutical Co., Ltd.	China NMPA approval No. H20113508; 2 mL:0.1 mg	Opioid analgesic used for perioperative analgesia and included in OME conversion when administered.
Flurbiprofen axetil injection	Beijing Tide Pharmaceutical Co., Ltd.	China NMPA approval No. H20041508; 5 mL:50 mg	Non-steroidal anti-inflammatory drug used as adjunctive postoperative analgesia when clinically indicated and not contraindicated.
Laryngoscope or video laryngoscope	Verathon	GlideScope video laryngoscope system	Representative device used to facilitate tracheal intubation after induction of general anesthesia.
Microsoft Excel	Microsoft Corp.	Microsoft Excel 2021 / Microsoft 365	Used for data organization, supplementary table preparation, and calculation verification before statistical analysis.
Multiparameter patient monitor	Mindray	BeneVision N15	Representative monitor used for ECG, noninvasive blood pressure, pulse oxygen saturation, end-tidal CO2, and body temperature monitoring.
Numerical Rating Scale (NRS)	Clinical assessment standard tool	11-point NRS, 0-10	Pain intensity scale used for resting postoperative pain assessment in PACU and at 6 h, 12 h, and 24 h after surgery.
Nursing documentation system	Anji County Hospital of Traditional Chinese Medicine	Institutional nursing documentation system	Used to extract postoperative NRS scores, PACU and ward nursing records, PONV documentation, time to first ambulation, and medication administration records.
Ondansetron hydrochloride injection	Qilu Pharmaceutical Co., Ltd.	Ondansetron hydrochloride injection; 2 mL:4 mg or 4 mL:8 mg	Antiemetic medication used for prevention or treatment of postoperative nausea and vomiting when clinically indicated.
Patient-controlled analgesia/infusion pump	ICU Medical / Smiths Medical	CADD-Solis VIP 2120	Representative infusion system used when patient-controlled or programmed opioid analgesia was clinically indicated.
Propofol injection	Fresenius Kabi	Propofol 1% MCT/LCT; China NMPA approval No. HJ20150657	Intravenous anesthetic used for induction and/or maintenance of general anesthesia.
Remifentanil hydrochloride for injection	Yichang Humanwell Pharmaceutical Co., Ltd.	China NMPA approval No. H20030199; 2 mg/vial	Short-acting opioid used for intraoperative analgesia or anesthesia maintenance according to institutional practice.
Rocuronium bromide injection	Guangdong Jiabo Pharmaceutical Co., Ltd.	China NMPA approval No. H20183109; 5 mL:50 mg	Nondepolarizing neuromuscular blocking agent used to facilitate tracheal intubation when selected by the attending anesthesiologist.
SPSS Statistics	IBM Corp.	Version 26.0	Software used for statistical analyses, including normality testing, homogeneity of variance testing, group comparisons, multivariable logistic regression, and model diagnostics.
Sufentanil citrate injection	Yichang Humanwell Pharmaceutical Co., Ltd.	China NMPA-approved sufentanil citrate injection; 1 mL:50 μg	Opioid analgesic used for perioperative analgesia and included in OME conversion when administered.