Table 4. Summary of the study design characteristics for the 27 studies included in the systematic review.
| Study Design Characteristics | Type | # Articles |
|---|---|---|
| Diseases Studied | Cancer | 14 |
| COPD | 9 | |
| CKD | 2 | |
| HIV/AIDS | 1 | |
| Cirrhosis | 1 | |
| Controls Used/Sub-analysis | Healthy controls | 17 |
| Surgical procedures for benign disease | 9 | |
| Chronic disease but no cachexia/ sarcopenia | 1 | |
| Sub-analysis* | 11 | |
| Matching Criteria | Age alone | 7 |
| Age and sex | 3 | |
| Age and airflow obstruction | 1 | |
| Not reported | 16 | |
| Assessment of Cachexia/ Sarcopenia** | Cachexia | 15 |
| Sarcopenia | 9 | |
| Cachexia and Sarcopenia | 3 | |
| Muscles Biopsied | Rectus abdominus | 13 |
| Quadriceps | 13 (9 vastus lateralis) | |
| Deltoid | 1 | |
| Technique used for Molecular Analysis | qPCR | 23 |
| Northern blot | 4 |
COPD = chronic obstructive pulmonary disease, CKD = chronic kidney disease, HIV/AIDS = human immunodeficiency virus/ acquired immunodeficiency syndrome, qPCR = quantitative polymerase chain reaction.
*Articles that included a sub-analysis of cases based on presence or absence of cachexia and/or sarcopenia or degree of weight loss. See Table 1 for details.
**Under the term cachexia we include assessment of weight loss and or body size. Under the term sarcopenia we include assessment of muscle mass or muscle strength. However, the terms cachexia and sarcopenia are not used consistently throughout the 27 articles.