Table 4.
Summary of findings–comorbidities.
| Meta-analysis | ||||||||
|---|---|---|---|---|---|---|---|---|
| Prognostic factor | OR (95% CI) | Overall quality | ||||||
| Alcohol abuse | 1.08 (0.96–1.20) | 6 (++++) | ||||||
| BMI < 18.5 vs. normal | 1.15 (0.45–2.98) | 4 (+++) | ||||||
| BMI 25–30 vs. normal | 0.91 (0.80–1.03) | 6 (++++) | ||||||
| BMI 30–35 vs. normal | 0.90 (0.80–1.02) | 6 (++++) | ||||||
| BMI 35–40 vs. normal | 0.84 (0.69–1.02) | 6 (++++) | ||||||
| BMI > 40 vs. normal | 1.05 (0.84–1.31) | 6 (++++) | ||||||
| Obesity | 1.06 (1.02–1.09) | 4 (+++) | ||||||
| Weight loss | 0.95 (0.71–1.27) | 3 (++) | ||||||
| Arrhythmias and AF combined | 1.14 (1.09–1.19) | 4 (+++) | ||||||
| Ischaemic heart disease (IHD) + coronary artery disease (CAD) + cardiac disease | 1.29 (0.79–2.09) | 3 (++) | ||||||
| Peripheral vascular disease | 1.17 (1.10–1.24) | 5 (+++) | ||||||
| Previous myocardial infarction, or coronary artery disease | 1.18 (0.29–4.88) | 3 (++) | ||||||
| Non-insulin-dependent diabetes mellitus (NIDDM) | 1.08 (0.80–1.45) | 4 (+++) | ||||||
| Liver disease | 1.29 (1.20–1.39) | 4 (+++) | ||||||
| Peptic ulcer disease | 0.94 (0.84–1.07) | 4 (+++) | ||||||
| Anaemia | 1.19 (1.15–1.24) | 6 (++++) | ||||||
| Deficiency anaemias | 1.06 (1.01–1.11) | 4 (+++) | ||||||
| Coagulopathy | 1.25 (1.15–1.36) | 4 (+++) | ||||||
| Fluid and electrolyte disorder | 1.05 (1.00–1.12) | 4 (+++) | ||||||
| Chronic pulmonary disease | 1.28 (1.22–1.34) | 3 (++) | ||||||
| Paralysis | 1.13 (0.97–1.31) | 4 (+++) | ||||||
| Psychiatric disorder | 1.43 (1.12–1.70) | 3 (++) | ||||||
| Smoking | 1.25 (0.82–1.91) | 5 (+++) | ||||||
| Rheumatologic disorder | 1.11 (1.04–1.18) | 3 (++) | ||||||
| Narrative Synthesis | ||||||||
| Prognostic factor | Univariate | Multivariate | Overall quality | |||||
| + | 0 | - | + | 0 | - | |||
| Composite comorbidity indices | ||||||||
| Charlson Comorbidity Index (CCI) 1-2 (reference category = 0) | - | - | - | 2 | - | - | 6 (++++) | |
| CCI 1 (reference category = 0) | - | - | - | 2 | 1 | - | 6 (++++) | |
| CCI 2 (reference category = 0) | - | - | - | 1 | - | - | 5 (++++) | |
| CCI ≥2 (reference category = 0) | - | - | - | 1 | 1 | - | 6 (++++) | |
| CCI 3-4 (reference category = 0) | - | - | - | 1 | - | - | 5 (+++) | |
| CCI ≥3 (reference category = 0) | - | - | - | 1 | - | - | 4 (+++) | |
| CCI 5+ (reference category = 0) | - | - | - | 1 | - | - | 5 (+++) | |
| Increasing CCI | - | - | - | - | 1 | - | 3 (++) | |
| Presence of any comorbidity | 1 | - | - | 2 | - | - | 4 (+++) | |
| Increasing American Society of Anaesthesiologists (ASA) classification (reference category = 2) | - | - | - | 1 | - | - | 4 (+++) | |
| Increasing ASA classification (reference category = 1) | - | - | - | - | 1 | - | 2 (+) | |
| ASA classification (other) | - | 1 | - | - | 1 | - | 2 (+) | |
| Increasing Elixhauser Index | - | - | - | 1 | - | - | 5 (+++) | |
| Increasing DRG (Diagnosis-related group) | - | - | - | 1 | - | - | 3 (++) | |
| Cardiovascular | ||||||||
| Hypertension | 2 | 2 | - | 6 | 1 | - | 5 (+++) | |
| Hyperlipidaemia | 1 | 1 | - | - | - | - | 4 (+++) | |
| Cardiac disease | - | - | - | 1 | - | - | 3 (++) | |
| Cardiovascular disease (CVD) | - | 1 | - | - | - | - | 3 (++) | |
| Congestive Cardiac/Heart Failure (CCF/CHF) | 3 | - | - | 5 | 2 | - | 5 (+++) | |
| Valvular disease | 1 | - | - | 2 | 1 | - | 3 (++) | |
| Peripheral vascular disease | 1 | 1 | - | - | 1 | - | 3 (++) | |
| History of percutaneous coronary intervention or cardiac surgery | 1 | - | - | - | - | - | 2 (+) | |
| BMI, obesity, and weight loss | ||||||||
| BMI (continuous) | - | 1 | - | 1 | 1 | - | 4 (+++) | |
| BMI underweight (reference category = overweight (25–30)) | - | - | - | - | 1 | - | 4 (+++) | |
| BMI normal weight (reference category = overweight (25–30)) | - | - | - | - | 1 | - | 4 (+++) | |
| BMI obese (reference category = overweight (25–30)) | - | - | - | - | 1 | - | 4 (+++) | |
| BMI very obese (reference category = overweight (25–30)) | - | - | - | - | 1 | - | 4 (+++) | |
| BMI morbidly obese (reference category = overweight (25–30)) | - | - | - | 1 | - | - | 4 (+++) | |
| BMI > 30 (reference category = normal weight) | - | - | - | 1 | - | - | 2 (+) | |
| Increasing BMI (reference category = <25) | - | 1 | - | - | - | - | 1 (+) | |
| Obesity | 1 | 1 | - | 2 | 1 | - | 2 (+) | |
| Morbid obesity | - | 1 | - | - | - | - | 2 (+) | |
| Weight loss | - | 1 | - | - | 1 | - | 4 (+++) | |
| Endocrine | ||||||||
| Diabetes (general category and Peskun type two diabetes mellitus (T2DM)) | - | 1 | - | 5 | 4 | - | 3 (++) | |
| Diabetes (with complications) | 1 | - | - | 1 | - | - | 5 (+++) | |
| Diabetes (without complications) | 1 | - | - | 1 | - | - | 5 (+++) | |
| Insulin-dependent diabetes mellitus (IDDM) | 1 | - | - | 1 | - | - | 5 (+++) | |
| NIDDM | 1 | - | - | - | 1 | - | 4 (+++) | |
| Hypothyroidism | - | 1 | - | - | 1 | - | 5 (+++) | |
| Gastrointestinal | ||||||||
| Liver disease | 1 | - | - | - | 1 | - | 2 (+) | |
| Haematological | ||||||||
| Anaemia | - | - | - | 1 | 1 | 1 | 4 (+++) | |
| Anaemia (blood loss) | 1 | - | - | - | 1 | - | 4 (+++) | |
| Anaemia (deficiency) | 1 | - | - | - | 2 | - | 3 (++) | |
| Bleeding disorders | 1 | - | - | 1 | - | - | 3 (++) | |
| Coagulopathy | 1 | - | - | - | - | - | 3 (++) | |
| Anticoagulant therapy | - | - | - | - | 1 | - | 2 (+) | |
| Increasing INR | 1 | - | - | 1 | - | - | 4 (+++) | |
| Fluid and electrolyte disorder | 1 | - | - | 1 | - | - | 3 (++) | |
| Elevated serum blood urea nitrogen (BUN) | 1 | - | - | 1 | - | - | 4 (+++) | |
| Hyponatraemia | - | 1 | - | - | 1 | - | 4 (+++) | |
| Low albumin | - | - | - | 1 | - | - | 4 (+++) | |
| Elevated creatinine | 1 | - | - | - | - | - | 3 (++) | |
| Elevated WBC count | 1 | - | - | - | - | - | 3 (++) | |
| Reduced haematocrit | 1 | - | - | - | - | - | 3 (++) | |
| Low platelets | 1 | - | - | - | - | - | 3 (++) | |
| Respiratory | ||||||||
| Chronic obstructive pulmonary disease (COPD) and chronic airways disease (combined) | - | - | - | 4 | - | - | 3 (++) | |
| Pulmonary disease | 1 | - | - | 1 | 1 | - | 4 (+++) | |
| Smoking | 1 | 2 | - | 1 | - | - | 3 (++) | |
| Pulmonary circulation disorder | - | - | - | 1 | 1 | - | 2 (+) | |
| Asthma | - | 1 | - | - | - | - | 1 (+) | |
| Dyspnoea | 1 | - | - | - | 1 | - | 3 (++) | |
| Previous pneumonia | - | - | - | - | 1 | - | 3 (++) | |
| Obstructive sleep apnoea | - | 1 | - | - | - | - | 1 (+) | |
| Cardiopulmonary disease | 1 | - | - | - | - | - | 0 (+) | |
| Psychiatric | ||||||||
| Depression | 1 | 2 | - | 3 | 1 | - | 5 (+++) | |
| ‘Other’ mental health condition (other than depression) | - | - | - | 1 | - | - | 3 (++) | |
| Bipolar disorder | - | 1 | - | - | - | - | 1 (+) | |
| Post-traumatic stress disorder (PTSD) | - | 1 | - | - | - | - | 1 (+) | |
| Anxiety disorder | - | 2 | - | - | - | - | 2 (+) | |
| Alcohol abuse | 1 | 2 | - | - | - | - | 3 (++) | |
| Drug abuse (including general substance abuse designation, and drug/alcohol abuse (combined category in Kurtz)) | 1 | 1 | - | 2 | - | - | 4 (+++) | |
| Psychoses | 1 | - | - | - | - | - | 2 (+) | |
| Neoplastic | ||||||||
| History of cancer | 1 | - | - | 2 | 1 | - | 4 (+++) | |
| Disseminated cancer | 1 | - | - | 1 | 2 | - | 3 (++) | |
| Lymphoma | - | - | - | 2 | - | - | 4 (+++) | |
| Neurological | ||||||||
| Previous stroke | - | 1 | - | 1 | - | 1 | 4 (+++) | |
| Dementia | - | - | - | 1 | - | - | 4 (+++) | |
| Other neurological disorder | 1 | - | - | 2 | 1 | - | 3 (++) | |
| In-hospital complications | ||||||||
| Deep vein thrombosis | - | - | - | 1 | - | - | 5 (+++) | |
| Pulmonary embolism | - | - | - | 1 | - | - | 5 (+++) | |
| Any complication | 1 | - | - | 1 | - | - | 6 (++++) | |
| Any medical complication | 1 | - | - | 1 | - | - | 4 (+++) | |
| Any surgical complication | 1 | - | - | 1 | - | - | 4 (+++) | |
| Urinary tract infection | - | - | - | 1 | - | - | 5 (+++) | |
| Surgical site infection | - | - | - | 1 | - | - | 5 (+++) | |
| Sepsis | 1 | - | - | - | 1 | - | 4 (+++) | |
| Cardiac (including cardiac arrest and myocardial infarction) | - | - | - | 1 | - | - | 4 (+++) | |
| Pneumonia | - | - | - | 1 | - | - | 5 (+++) | |
| Acute renal failure | - | - | - | 1 | - | - | 5 (+++) | |
| Cerebrovascular accident (CVA) or transient ischaemic attach (TIA) | 1 | - | - | - | - | - | 3 (++) | |
| Renal | ||||||||
| Chronic kidney disease (CKD) | 1 | - | - | 2 | 1 | - | 5 (+++) | |
| Dialysis dependence | - | - | - | 1 | - | - | 4 (++) | |
| Renal failure–acute, preoperative | - | - | - | - | 1 | - | 4 (++) | |
| Renal failure/disease–chronicity unspecified | 1 | - | - | 5 | - | - | 6 (++++) | |
| Rheumatological and autoimmune | ||||||||
| Rheumatoid arthritis/collagen vascular diseases | 1 | - | - | - | - | - | 3 (++) | |
| Steroid or other immunosuppressant use for chronic condition | - | - | - | 1 | - | - | 3 (++) | |
| Other | ||||||||
| Preoperative opioid use | - | - | - | 2 | 1 | - | 3 (++) | |
| Post-discharge opioid use | - | - | - | 1 | - | - | 1 (+) | |
| Preoperative medication use (general) | - | - | - | 1 | - | - | 3 (++) | |
| Preoperative medication use (analgesics) | - | - | - | 1 | - | 1 (+) | ||
| Preoperative medication use (anticonvulsants) | - | - | - | 1 | - | - | 2 (+) | |
| Preoperative medication use (Serotonin–norepinephrine reuptake inhibitor (SNRIs)) | - | - | - | - | 1 | - | 2 (+) | |
| Preoperative medication use (Tricyclic antidepressants (TCAs)) | - | - | - | - | 1 | - | 2 (+) | |
| Preoperative medication use (sedatives) | - | - | - | - | 1 | - | 2 (+) | |
| Wound class | 1 | - | - | - | 2 | - | 4 (+++) | |
Overall quality: + very low quality = very little confidence in the effect estimate: true effect likely to be substantially different from the estimate of effect; ++ low quality = confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the study; +++ moderate quality = moderately confident in the effect estimate: true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different; ++++ high quality = very confident that the true effect lies close to that of the estimate of the effect.