The Impact of Metabolic Status on Pain and Central Sensitization in Women With Lipedema: A Cross-Sectional Observational Study

Central Sensitization Inventory (CSI)

The Central Sensitization Inventory is a self-report screening tool developed to assess the presence and severity of symptoms associated with central sensitization. The inventory evaluates symptoms reflecting sensitization in central nervous system pain-processing mechanisms, including widespread pain, fatigue, sleep disturbances, and cognitive complaints. The CSI consists of 25 items, each scored on a scale from 0 to 4, with a total score ranging from 0 to 100. A total score of 40 or higher is considered to be associated with a high likelihood of central sensitization.

Numeric Rating Scale (NRS)

The Numeric Rating Scale (NRS) is used to measure and monitor pain intensity. A score of "0" represents no pain, while "10" indicates the worst pain imaginable. Patients are asked to rate their pain on a scale from 0 to 10. Due to its simplicity and ease of understanding, this scale is frequently used in clinical research.

Fatigue Severity Scale (FSS)

The Fatigue Severity Scale is a self-report measure used to evaluate the impact of fatigue on daily life and functional activities. The scale consists of 9 items, each scored on a scale from 1 to 7. Higher average scores indicate greater fatigue severity.

Neuropathic Pain Diagnostic Questionnaire (DN4)

The DN4 questionnaire was developed to assess the presence of neuropathic pain. It consists of 10 items derived from symptom-based questions and clinical examination findings. The total score ranges from 0 to 10, and a score of 4 or higher is considered indicative of neuropathic pain.

Short Form-12 (SF-12)

The Short Form-12 is a questionnaire used to assess general health status and health-related quality of life. It consists of 12 items. Scores range from 0 to 100, with higher scores indicating better quality of life.

HOMA-IR (Homeostatic Model Assessment of Insulin Resistance)

HOMA-IR is an index widely used to assess insulin resistance and is calculated using fasting glucose and fasting insulin levels. In this study, HOMA-IR will be calculated using the following formula: HOMA-IR = \[Fasting insulin (µIU/mL) × Fasting glucose (mg/dL)\] / 405. Although there is no universally accepted single cut-off value for HOMA-IR, studies conducted in adult populations commonly interpret HOMA-IR values as follows: \<1.0 indicates normal insulin sensitivity, 1.0-1.9 borderline insulin resistance, and ≥2.0 suggestive of insulin resistance; particularly HOMA-IR ≥2.5 is frequently used as a threshold indicating insulin resistance. In this study, HOMA-IR will be evaluated both as a continuous variable and categorized according to these commonly used reference values in the literature.

Triglyceride/HDL Cholesterol (TG/HDL) Ratio

The TG/HDL ratio is a metabolic indicator obtained by dividing the serum triglyceride level by the high-density lipoprotein cholesterol (HDL) level and is associated with atherogenic dyslipidemia and insulin resistance. In this study, the TG/HDL ratio will be calculated using the formula TG (mg/dL) / HDL (mg/dL). Although there is no universally accepted cut-off value for the TG/HDL ratio, studies conducted in adult populations commonly classify values as follows: \<2.0 normal, 2.0-3.0 borderline, and ≥3.0 indicative of increased metabolic risk; particularly TG/HDL ≥3.5 is frequently considered associated with insulin resistance and increased cardiometabolic risk. In this study, the TG/HDL ratio will be categorized according to these commonly used reference values in the literature.

Waist-to-Hip Ratio

The waist-to-hip ratio is calculated by dividing waist circumference by hip circumference and is used to assess abdominal fat distribution. In women, a value of ≥0.85 is considered indicative of central obesity and increased cardiometabolic risk.