Serum Potassium as a Predictor of Clinical Outcomes in an Older Patient Cohort With Chronic Postsurgical Pain

Chinese PLA General Hospital3,088 enrolled

Overview

Perioperative serum potassium in patients over 65 impacts recovery, quality of life and physical functioning. While perioperative serum potassium is an important preoperative risk factor for poor surgical outcomes in older adults, the relationship between perioperative serum potassium and postsurgical pain in this population has not been investigated. The investigators hypothesized that preoperative serum potassium would be associated with greater odds of postsurgical chronic pain.

This study is a secondary interim analysis of 'Perioperative Database of Chinese Elderly Patients,' an ongoing prospective observational cohort study that began in 2020 at the muti-center in China with the primary aim of complications in older adults before and after surgery. The investigators described the demographics, comorbidities, and assessment scores as n (percentage) or mean (SD), as appropriate. Unadjusted bivariate analyses included t-test or χ2 test to compare differences between minimal pain and intrusive pain at 3 months after surgery based on demographics, preoperative status, baseline pain status and perioperative serum potassium. The investigators then created a logistic regression model with the outcome of persistent pain at 3 months after surgery and serum potassiumas the main predictor, adjusting for baseline pain, surgery type and surgery part and frailty status based on the hypothesis and association. The investigators also tested for the interaction between baseline pain and serum potassiumas.

Study Type

OBSERVATIONAL

Enrollment

3,088

Conditions

Potassium, Decreased Level Postsurgical Pain, Chronic

Interventions

Eligibility

Sex: ALLMin age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Geriatric surgical patients ≥65 years old * Diagnosis of Chronic postsurgical pain (CPSP) CPSP was made based on the guidelines of the International Society for Pain (CPSP: ICD-11) as follows: Chronic postsurgical pain is chronic pain developing or increasing in intensity after a surgical procedure and persisting beyond the healing process, i.e. at least 3 months after surgery. The pain is either localised to the surgical field, projected to the innervation territory of a nerve situated in this area, or referred to a dermatome (after surgery/injury to deep somatic or visceral tissues). Other causes of pain including infection, malignancy etc. need to be excluded as well as pain continuing from a pre-existing pain problem. Dependent on type of surgery, chronic postsurgical pain often may be neuropathic pain. Exclusion Criteria: * Patients in the central nervous system group were excluded from cardiac and neurosurgery, patients in the heart injury group were excluded from cardiac surgery. * patients who did not agree to participate in the study were excluded in all groups.

Outcomes

Primary Outcomes

Pain trajectories after surgery (Numerical Rating Scale)

Pain intensity was assessed using a numerical rating scale (NRS) from 0 to 10, with zero representing no pain and 10 representing worst imaginable pain. The worst pain intensity was then categorized into two groups: no or mild pain (NRS from 0 to 3) and moderate to severe pain (NRS from 4 to 10).

Time frame: Up to 3 months postoperation

The Brief Pain Inventory-short form

It measured pain location in the body; pain intensity on an 11-point numerical rating scale (NRS; 0 represents "no pain" and 10 the "worst pain imaginable"); analgesic intake; perception of analgesic relief; and pain interference with daily life on an 11-point NRS (0 "does not interfere and 10"completely interferes") indistinct dimensions (general activity, mood, walking, work, relations with others, sleep, and enjoyment of life). Higher scores represent higher levels of pain interference.

Time frame: Up to 3 months postoperation

Secondary Outcomes

Pain Catastrophizing Scale (PCS)

The PCS consists of 13 items, and each item is answered with a numeric value between 0 and 4; 0 corresponding to "not at all", and four corresponded to "all the time". Higher scores indicate a higher level of pain catastrophizing, the Chinese version of the PCS has demonstrated a good reliability and validity (Cronbach's alpha was 0.87 and the ICC was 0.97)

Time frame: within 30 days prior to surgery ,Up to 3 months postoperation

The trajectories of health related quality of life(HRQoL)

The trajectory of HRQoL is the vector of Utility values measured with EuroQol five-dimensional questionnaire(EQ-5D-5L)taken over 3 months(days 1, 3, 7, 30, 90；Day 0 is the day of surgery). The EQ-5D-5L measures health on five domains (mobility, self-care, usual activities, pain discomfort, and anxiety-depression), and the scores will be combined using Chinese general population weights to generate a single utility or index score. Utility values for the EQ-5D range from 1.00 to -0.391, where a score of 0 and 1 are regarded as equivalent to death and 'perfect health', respectively, and a score \< 0 is considered as health state that is 'worse than death'.

Time frame: within 30 days prior to surgery , 1, 3, 7, 30, 90 days postoperation

The Frail Scale

Frailty was assessed prior to surgery using the Frail Scale assessment. The Frail Scale assessment is a validated 5-item scale comprising components from the Cardiovascular Health Frailty Index and Rockwood Scale. The five components measured include fatigue, resistance, ambulation, illness and loss of weight. For each item, choose "yes" and "no", "No" is assigned 0 points, "yes" is assigned 1 point.The total score of the five items is 0-5. (zero representing no frilty and 5 representing worst imaginable frilty.) Patients were classified as frail if they scored 3 or more on the 5-point scale and not frail if they scored below 3.