Patients undergoing breast cancer surgery who had preoperative vitamin D deficiency may have higher rates of moderate to severe pain at 12 hours post-surgery.
In a prospective observational study, researchers enrolled 184 female patients aged 20 to 65 years with newly diagnosed, histopathologically confirmed breast cancer who were scheduled for elective unilateral modified radical mastectomy between September 2024 and April 2025.
The patients were categorized according to preoperative serum 25-hydroxyvitamin D levels into a vitamin D-deficient group with levels below 30 nmol/L (n = 92) and a vitamin D-sufficient group with levels of 30 nmol/L or greater (n = 92).
The primary endpoint was moderate to severe postoperative pain, defined as a Numerical Rating Scale score greater than 3 at 12 hours postsurgery. At that time point, 17% of the patients in the vitamin D-deficient group reported moderate to severe pain compared with just 2% of those in the vitamin D-sufficient group.
Immediately following surgery, pain scores were similar between the groups. At 6 hours, moderate to severe pain occurred in about 33% of the patients with vitamin D deficiency vs 20% of patients with sufficient vitamin D levels.
The researchers also evaluated cumulative pain scores during the first 24 hours using area under the curve analysis.
All of the patients received standardized anesthesia and postoperative analgesia protocols that included intravenous paracetamol and patient-controlled tramadol analgesia.
Mean intraoperative fentanyl consumption was 113 µg in the vitamin D-deficient group compared with 105 µg in the vitamin D-sufficient group. Mean postoperative tramadol consumption during the first 24 hours was 381 mg vs 268 mg, respectively.
Because the number of moderate to severe pain events at the 12-hour primary endpoint was low, the researchers used a secondary composite outcome for multivariable logistic regression that included moderate to severe pain occurring at any postoperative assessment during the first 24 hours.
After adjustment for age, body mass index, American Society of Anesthesiologists (ASA) physical status, surgery duration, and fentanyl consumption, vitamin D deficiency remained independently associated with more than three times the odds of moderate to severe postoperative pain during the first 24 hours.
Baseline characteristics, including age, body mass index, ASA physical status, preoperative pain scores, and surgery duration, were similar between the two groups.
Postoperative nausea occurred in a greater proportion of the patients in the vitamin D-deficient group compared with those in the vitamin D-sufficient group. No patients experienced respiratory depression.
The researchers reported that no patients in either group experienced severe pain, defined as a Numerical Rating Scale score of 7 or greater, during the study period.
The study was conducted at a single center, and all participants were Egyptian, which researchers said may limit generalizability. Additional limitations included the short follow-up period and lack of assessment of inflammatory markers, anxiety, depression, cancer stage, neoadjuvant therapy, or sleep disturbance.
The study authors reported no competing interests and no specific funding for the study.
