Abstract
Understanding the contribution of host factors, including age, nutrition, and immunosuppression, to patient outcomes enables surgeons to more appropriately preoperatively counsel patients and more effectively coordinate ancillary services to optimize outcomes. A working knowledge of the effect of comorbidities, including obesity, diabetes, and heart disease, upon patient mortality enables urologic surgeons to risk stratify patients and better define appropriate surgical candidates. As bundled payments and reimbursement for quality become the norm, increased attention to host factors and comorbidities is necessary to minimize the risk of postoperative complications and optimize patient care.
Keywords
Complications, surgical, Comorbidities, quantifying, Host factors, Obesity, Infection, Malnutrition, Nutritional status assessment, Cancer, prostate, Cancer, bladder, Cancer, kidney
Key Points
- 1.
With increasing life expectancy in the general population, the prevalence of comorbid conditions such as obesity, heart disease, and diabetes has increased to alarming proportions.
- 2.
Awareness of comorbidities allows the urologist to institute the proper measures to control preexisting diseases to optimize the overall health status of the individual patient, maximize the likelihood of a good outcome, and minimize the risk of a complication.
- 3.
Obesity can directly influence surgical outcome because of certain proposed biologic linkages with urologic malignant diseases.
- 4.
Nutritional status is a key clinical parameter demanding thorough evaluation in the surgical patient to prevent nutrition-related complications.
- 5.
Given that certain host factors predispose the urologic patient to complicated infection, it is necessary to determine the need for antimicrobial prophylaxis preoperatively and to prevent the occurrence of systemic septicemia.
Every urologist would prefer that any patient who has a consultation for a urologic disease would be solely afflicted with the disease for which he or she seeks medical attention, that every surgical patient would be healthy enough to tolerate the proposed surgical intervention to treat the condition, and that complications would occur with only miniscule probability. Unfortunately, this situation is far removed from reality and certainly is becoming less common in current clinical practice in which medical histories, physical examinations, preoperative laboratory examinations, and imaging scans are likely to reveal coexisting medical problems in the urologic patient.
In the present era, with life expectancy ever increasing, the prevalence of comorbid conditions such as obesity, heart disease, and diabetes, which affect urologic diseases and their clinical outcome following management, has congruently reached alarming proportions in the general population. Whether driven by improved medical science, rapid technologic advancement, or an effect of natural selection, men and women are living longer ( Fig. 1.1 ). The medical community recognizes special considerations for elderly patients, and most of these considerations are brought about by medical conditions that are diagnosed in later life and progress with advancing age. In urologic disease entities such as erectile dysfunction in men, pelvic floor disorders in women, and urologic malignant diseases such as prostate and bladder cancer, the predisposition and clinical effects related to advanced age have direct biologic implications for the urologic condition. Moreover, because most of these disease entities are diagnosed in the more mature stages of life, the probability of preexisting medical conditions in these patients at the time of consultation is high.
Notwithstanding the effect of age on comorbid medical conditions in the urologic patient, the past decades have also seen a dramatic rise in the prevalence of disease entities closely linked to harmful lifestyle choices such as smoking and alcohol consumption, unhealthy diets, lack of physical activity, and intravenous drug abuse. These lifestyle choices adversely affect patients of all ages who may seek urologic consultation and who may present with detrimental comorbidities such as childhood obesity, juvenile diabetes, chronic obstructive pulmonary disease, liver disease, and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS).
Although biologic links to known urologic diseases may be less apparent, the overall outcome and incidence of complications following surgical intervention are directly affected by coexisting health problems. Indeed, assessing the urologic patient for preexisting comorbidities is of critical importance because host factors play an important role in postoperative complications. Awareness of comorbidities allows the urologist to institute the proper measures to control preexisting diseases to optimize the overall health status of the individual patient, maximize the likelihood of a good outcome, and minimize the risk of a complication. The urologist also can assess the need for ancillary examinations for a more comprehensive evaluation of comorbid conditions more accurately and can determine the need for intraoperative monitoring and specialized intensive postsurgical care. More importantly, comprehensive knowledge of all concurrent illnesses in the urologic patient aids the urologist in deciding whether surgical intervention is the optimal treatment option or whether conservative management may be the best therapeutic alternative.
To serve as an introduction to the succeeding chapters in this section, we tackle host factors that significantly affect the occurrence of nonurologic complications following urologic surgery. We provide an overview of comorbidities in the urologic patient and highlight current prevalent disease entities that influence outcome following definitive surgical management. Comorbidities to which whole chapters are devoted, such as those pertaining to cardiovascular, pulmonary, hematologic, and anesthetic complications, are discussed only briefly here, to leave room for a more detailed discussion of topics of special interest such as obesity that are of major interest in the field of contemporary urology. We also provide insight into clinical tools such as useful comorbidity indices and scoring systems that aim to quantify the severity of comorbidities and predict posttreatment morbidity and mortality.
Obesity
The importance of nutritional status to surgical outcomes and the deleterious effects of obesity are of significant interest in the field of urology. Interest has centered on obesity for two main reasons: First, the prevalence of obesity has been growing at epidemic proportions worldwide, and second scientific evidence suggests a relationship between obesity and multiple urologic conditions including benign prostatic hyperplasia (BPH), urologic malignant diseases, incontinence, erectile dysfunction, and stone disease, to name a few.
Most of the leading causes of death in the United States are linked to obesity, including heart disease, cancer, stroke, and diabetes. Viewed as a growing national health crisis, obesity is the second leading cause of preventable death; obesity not only results in a potentially avoidable toll in human lives but also incurs a substantial cost in health expenditure for the country. Affecting over one-third of all adults in the United States, obesity is further associated with various comorbidities, such as hypertension, sleep apnea, cholecystolithiasis, osteoarthritis, and depression, that may aggravate the overall health status of the overweight or obese patient and may contribute to surgical complications. Childhood obesity is also on the rise and could have undesirable consequences for children and adolescents undergoing pediatric urologic procedures.
Obesity is defined as an excess accumulation of adipose tissue in the body; however, functionally, overweight and obese are labels used to denote ranges of weight that are in excess of what is generally considered healthy for the given height of a person. Because of its simplicity, body mass index (BMI) is a widely accepted method to assess for obesity. BMI is calculated by dividing the weight (in kilograms) of an individual by the height (in meters) squared. Fig. 1.2 illustrates the standard weight status categories associated with BMI range for adults. Although other anthropometric measurements such as skinfold thickness and midarm circumference may be used for more accurate estimation of body fat, these measurements are not routinely recorded in clinical practice and are of limited availability for retrospective studies.
Fat distribution may also be an important determinant of obesity because individuals with high BMI who have upper body fat distribution (android) have been shown to be at greater risk for comorbidities such as cardiovascular disease, cerebrovascular disease, and hypertension compared with men and women who have lower body fat distribution (gynecoid). Newer studies found better accuracy in gauging obesity with the use of waist circumference and waist-to-hip ratios; however, these parameters are more cumbersome to measure compared with BMI. Central obesity correlates with visceral fat accumulation in the abdomen and is diagnosed when the waist-to-hip ratio exceeds 1.0 in men and 0.9 in women. This condition is in contrast to peripheral obesity , in which fat accumulation occurs subcutaneously in the gluteofemoral region. However, the distinction is clinically important because central obesity imparts a significantly higher risk of insulin resistance and type 2 diabetes, blood lipid disorders, hypertension, and heart disease compared with peripheral obesity.
The medical consequences of obesity result in part from increased secretion of pathogenic macromolecules from enlarged adipose cells. Increased release of fatty acids from fat cells that are stored in the liver or muscle results in the insulin-resistant state that is commonly seen in obesity. Diabetes ensues as the mounting insulin resistance overwhelms the secretory response of the pancreas. Bioactive cytokines, particularly interleukin-6, released from adipocytes promote the proinflammatory state that is characteristic of obesity. Secretion of prothrombin activator inhibitor-1 from adipose cells, coupled with impaired endothelial function, plays a key role in the hypercoagulable state of obesity and ultimately increases the risk of cardiovascular disease, stroke, and hypertension in obesity. This prothrombotic state is further aggravated directly by increased estrogen levels and is complicated indirectly by decreased antiangiogenic cytokines such as adiponectin. The overall effect of these multiple pathologic consequences of increased fat stores is the risk of shortened life expectancy.
Obesity and Urologic Malignant Diseases
Investigations since the late 1980s have sparked keen interest in the link between obesity and urologic cancer, especially for prostate adenocarcinoma and kidney cancer. Investigators have hypothesized that diet and obesity affect the underlying biologic mechanisms that ultimately lead to carcinogenesis, including promotion of angiogenesis and mitogenesis, increased cellular proliferation, impairment of immune response, increased exposure to oxidative damage by free radicals, and promotion of a proinflammatory state. Obesity can directly influence surgical outcome as a result of these proposed biologic linkages with urologic malignant diseases.
Prostate Cancer
Because obese men with prostate cancer have lower serum prostate-specific antigen (PSA) levels relative to men of normal weight, and because physical assessment of the prostate through digital rectal examination is hindered by adiposity, detection of prostate cancer among men with a high BMI may be delayed. Performing a transrectal ultrasound–guided biopsy to establish a tissue diagnosis of prostate cancer can also be more technically difficult in obese men, and because of prostatic enlargement, some cancers may be missed by undersampling. After histopathologic confirmation of prostate cancer, the patient may opt for surgical treatment, but urologists may be reluctant to operate on morbidly obese patients for several reasons. The anesthetic risks pertaining to adequacy of ventilatory support and difficulty in fluid monitoring are further complicated by the increased incidence of comorbid conditions such as hypertension, heart disease, stroke, and diabetes.
If the urologist does perform surgery, adiposity can be a physical hindrance that may curtail adequate exposure of the surgical field, particularly when a retropubic approach is planned for access to the prostate. Among men undergoing an open retropubic prostatectomy, increasing BMI is associated with increasing operative time and increasing intraoperative blood loss. For these reasons, some urologists have advocated that perineal prostatectomy or a robotic-assisted laparoscopic prostatectomy should be favored over an open retropubic approach for treatment of obese men with prostate cancer. However, a study by Fitzsimons and associates suggested that both perineal and open retropubic approaches have comparable outcomes in terms of estimated blood loss and operative time for obese patients. In contrast, Ellimoottil and colleagues found lower transfusion rates among 9108 obese men undergoing robotic-assisted laparoscopic prostatectomy versus an open retropubic approach; however, no difference in perioperative complications between the groups was identified. In a matched pair analysis including 255 patients, Beyer et al. reported lower blood loss, transfusion rates, and fewer 30-day complications among obese men undergoing a robotic-assisted laparoscopic prostatectomy as compared to those undergoing an open retropubic prostatectomy.
Beyond technical issues, obesity may also influence the oncologic outcome among men undergoing radical prostatectomy. First, earlier studies found an increased incidence of positive surgical margins and capsular incision among men with higher BMIs. Similarly, men with higher BMIs present with higher-grade tumors and more advance pathologic stages of disease. On postsurgical follow-up, men with an elevated BMI (≥30 kg/m 2 ) are at significantly increased risk of biochemical recurrence relative to men with a lower BMI, as denoted by an elevated postoperative PSA test result (>0.2 ng/mL or two values at 0.2 ng/mL). More ominously, increased body weight was found to be associated with an increased risk of death from prostate cancer in a large, prospectively studied population. Thus, obesity may well exert a biologic effect on prostate cancer that promotes aggressiveness and disease progression. However, in terms of health-related quality of life after radical prostatectomy, prospective studies have so far failed to demonstrate large differences between mildly obese men and men of normal weight. For a more detailed review of obesity and prostate cancer, we recommend the article by Allott and Freedland in European Urology .
Kidney Cancer
Obesity, particularly in women, has been shown to be associated with renal cell carcinoma (RCC). A high BMI was found to be a strong risk factor for RCC; several underlying mechanisms were suspected, including higher insulin and estrogen levels, hypertension, hypercholesterolemia, and impaired host immune response. Boeing and colleagues examined determinants such as smoking, diet, occupational hazards, beverage consumption, medications, and obesity in a case-control cohort of 277 patients with RCC and 286 matched controls and found that specific dietary patterns associated with obesity, such as consumption of fatty foods and meat products, may explain the higher incidence of RCC in industrialized countries relative to developing countries. Indeed, in a large retrospective study involving 363,992 men, investigators from the National Institutes of Health found that obese men, especially those with a history of tobacco use and elevated systolic blood pressures, have an increased long-term risk for RCC.
As in prostate cancer, open surgical procedures for RCC can be technically difficult in patients with severe adiposity. Thus, wide interest exists in prescribing minimally invasive procedures for obese patients because these approaches have been found to be safe and effective for this subset of patients. While BMI was found to be a significant risk factor for major postoperative complications in patients treated with laparoscopic surgery for RCC, more recent literature evaluating robotic-assisted laparoscopic procedures have found no association between obesity and complication rates. Finally, with regard to clinical outcome and cancer-specific mortality, overweight and obese patients have a higher risk of death from kidney cancer relative to patients of normal weight.
Bladder Cancer
Compared with prostate and renal cancer, published reports of relationships between bladder cancer and obesity are scarce. In 1994, an epidemiologic study of 514 patients with bladder cancer found that beyond the well-known link with smoking, obesity was also a significant risk factor for bladder cancer. This was substantiated in a recent case control study, in which patients with metabolic syndrome were at a twofold higher risk of bladder cancer. However, a large prospective study of nearly 1 million people found no link between BMI and bladder cancer mortality. With regard to diet, reports on the association between high fat intake and bladder cancer have been conflicting.
With respect to surgical outcome for radical cystectomy, abundant reports show not only that obesity contributes to the technical challenge of the operation but also that higher BMI increases the risk of perioperative complications. In a retrospective analysis of 304 consecutive patients who underwent radical cystectomy and urinary diversion for bladder cancer, increased BMI was independently associated with higher estimated blood loss. This finding was later confirmed in a cohort of 498 patients; the investigators concluded that, along with greater blood loss, an increased BMI was also independently associated with prolonged operative time and increased rate of complications. In limited robotic cystectomy case series, increasing BMI was not associated with prolonged operative times or increased blood loss, though it was associated with an increased rate of 90-day re-admission.
Obesity and Benign Urologic Conditions
Several nonmalignant urologic conditions are also unfavorably affected by an increased BMI and morbid obesity.
Benign Prostatic Hyperplasia and Lower Urinary Tract Symptoms
Obesity is a known risk factor for lower urinary tract symptoms (LUTS) and BPH. Indeed, a large-scale, cross-sectional study from the Prostate Study Group of the Austrian Society for Urology found a link between BPH and obesity. The relationship between obesity and LUTS was further confirmed in a report from Johns Hopkins University in Baltimore on 2797 men from the Third National Health and Nutrition Examination Survey. In another confirmatory study, BPH was found to be associated with increased serum insulin levels and abdominal obesity as opposed to BMI itself. The biologic link between obesity and BPH likely has its origin in the association of obesity with hyperinsulinemia and the status of insulin as a direct prostate growth factor.
Erectile Dysfunction
Obesity, particularly central obesity, is a known predictor of erectile dysfunction in men. Both atherosclerosis and diabetes mellitus, which are associated with obesity, play significant roles in the development of erectile dysfunction. Although the underlying cause for erectile dysfunction is thought to be multifactorial, investigators have suggested that obesity increases the risk of erectile dysfunction of vascular origin as a result of the development of chronic vascular disease. Obesity is also known to increase the risk of diabetes. The microvascular complications characteristic of diabetes exert deleterious effects on erectile tissue similar to the pathologic features of diabetic nephropathy, retinopathy, and gastroparesis. Furthermore, weight loss is the only known lifestyle intervention that can improve erectile dysfunction.
Stress Urinary Incontinence
Pelvic floor weakness leading to stress urinary incontinence (SUI) in women is aggravated by increased intraabdominal pressure and is closely associated with truncal obesity. A report examined the association of bladder function with smoking, food consumption, and obesity in 6424 women with SUI and found a strong relationship between SUI and obesity. These findings were confirmed in a questionnaire-based study conducted in Norway involving 27,936 women. The proposed underlying mechanism for the association between high BMI and incontinence is that a high BMI leads to increased intravesical pressures and thus lowers the differential between the detrusor pressure and leak point pressure such that incontinence is more likely to occur. With regard to the perioperative effect of obesity in surgical treatment of SUI, a study involving 250 women who underwent retropubic anti-incontinence procedures revealed that operative time was significantly longer for obese women; however, blood loss and major perioperative complications were similar across BMI groups.
Urolithiasis
Urinary stone formation has been linked to obesity, as illustrated by a report on 527 calcium oxalate stone formers wherein an increased BMI was strongly associated with an elevated risk of stone formation for both men and women. However, a retrospective study of 5492 stone formers revealed that the association between obesity and stone formation was significant only in women. In a study conducted at Duke University, the major metabolic abnormalities found in obese stone formers that were possible contributors to recurrent stone formation were hypocitraturia, gouty diathesis, and hyperuricosuria. An inverse association between pH and body weight suggests that production of excessively acidic urine promotes uric acid nephrolithiasis in obese stone formers.
With respect to urologic procedures to treat stone disease, obesity adversely affects outcome following extracorporeal shock wave lithotripsy (ESWL). In a report examining clinical and radiologic variables associated with poor outcome after ESWL, along with obesity, pelvic ureteral stones, stones >10 mm, and obstruction were independent predictors of unsuccessful outcome. Thus, because of the probability of treatment failure, obese patients, particularly those with a skin-to-stone distance of >10 cm, may be better served by endourologic procedures than by ESWL.
Malnutrition
At the opposite end of the nutritional spectrum from overnutrition and obesity is malnutrition. With regard to the surgical patient, malnutrition has been associated with an increased incidence of nosocomial infection, poor wound healing, an increased length of hospital stay, multiorgan dysfunction, and mortality. Various scientific investigations have demonstrated that deterioration of nutritional status has an invariably deleterious effect on surgical outcome. As early as 1932, Cuthbertson reported the association of impaired wound healing with negative nitrogen balance in trauma patients. A more recent prospective study conducted in a cohort of patients who did not have cancer used four clinical parameters to predict perioperative morbidity:
- 1.
Percentage of ideal body weight
- 2.
Preoperative percentage of weight loss
- 3.
Arm muscle circumference
- 4.
Serum albumin.
Results of the study revealed that patients with at least one abnormal clinical parameter had a significant increase in the incidence of major complications and in length of hospital stay relative to patients with normal preoperative parameters. Not only has malnutrition per se been implicated in surgical complications but also certain types of nutrient deficiency, protein malnutrition in particular, may lead to more severe postoperative problems. Relative to protein-calorie malnutrition, which is characterized by a lack of both proteins and carbohydrates, severe protein malnutrition leads to low serum albumin concentration, edema, and a high prevalence of acute infections. Thus, it is evident that nutritional status is a key clinical parameter demanding thorough evaluation in the surgical patient to prevent nutrition-related complications.
Nutritional Status Assessment
Traditionally, clinicians relied on anthropometric measurements, which they compared with tables providing ideal weight-for-height estimates to evaluate the nutritional status of patients. Clinicians also determined body mass composition determinants such as lean body mass based on limb skinfold or circumference measurements and used these variables as indicators for adequacy of nutrition. However, problems pertaining to the precision of anthropometric measurements, wide intra-observer and inter-observer variations, and the lack of reliable reference standards have challenged the validity of these methods in ascertaining nutritional health of the surgical patient. These issues surrounding the traditional methods of screening for malnutrition led to an interest in studying serum markers for more accurate determination of preoperative nutritional competence. However, the use of serum markers to diagnose malnutrition is fraught with inaccuracy, as the most commonly used serum markers, albumin and prealbumin, are affected by multiple conditions other than malnutrition, including inflammation, liver disease, and kidney disease.
In the absence of reliable serum markers to judge nutritional status and challenges applying anthropometric measurements, the next best option for nutritional assessment may be screening tools such as the Malnutrition Universal Screening Tool (MUST) or the NRS 2002. MUST was designed to be used in the community and factors in BMI, weight loss, and acute disease effect, with referral to a dietitian recommended for a score ≥2 ( Fig. 1.3 ). The NRS 2002, validated for in-hospital use, provides an initial screening based upon a BMI <20.5, recent weight loss, reduced dietary intake, and the presence of severe illness ( Tables 1.1 and 1.2 ). During an inpatient hospitalization, nutritional plans are advised for patients with NRS-2002 scores of ≥3.
| 1 | Is BMI <20.5? | Yes | No |
| 2 | Has the patient lost weight within the last 3 months? | ||
| 3 | Has the patient had a reduced dietary intake in the last week? | ||
| 4 | Is the patient severely ill? (e.g., in intensive therapy?) | ||
| Yes: If the answer is ‘Yes’ to any question, the screening in Table 1.2 is performed. No: If the answer is ‘No’ to all questions, the patient is re-screened at weekly intervals. If the patient, e.g., is scheduled for a major operation, a preventive nutritional care plan is considered to avoid the associated risk status. | |||
| Impaired Nutritional Status | Severity of Disease (≈ Increase in Requirements) | ||
|---|---|---|---|
| Absent Score 0 | Normal nutritional status | Absent Score 0 | Normal nutritional requirements |
| Mild Score 1 | Wt loss >5% in 3 mths or food intake below 50–75% of normal requirement in preceding week | Mild Score 1 | Hip fracture * Chronic patients, in particular with acute complications: cirrhosis * , COPD * . Chronic hemodialysis, diabetes, oncology |
| Moderate Score 2 | Wt loss >5% in 2 mths or BMI 18.5–20.5 + impaired general condition or food intake 25–60% of normal requirement in preceding week | Moderate Score 2 | Major abdominal surgery * Stroke * Severe pnuemonia, hematologic malignancy |
| Severe Score 3 | Wt loss >5% in 1 mnth (>15% in 3 mths) or BMI <18.5 plus impaired general condition or food intake 0–25% of normal requirement in preceding week | Severe Score 3 | Head injury * Bone marrow transplantation * Intensive care patients (APACHE >10) |
| Score | + | Score | = Total Score |
| Age | If ≥70 years: add 1 to total score above | = age-adjusted total score | |
| Score ≥3: the patient is nutritionally at risk, and a nutritional care plan is initiated. Score <3: weekly screening of the patient. If the patient, e.g., is scheduled for a major operation, a preventive nutritional care plan is considered to avoid the associated risk status. | |||
Related posts:
Complications of the Incision and Patient Positioning
Complications of Transurethral Resection of Bladder Tumors
Complications of Radical Cystectomy and Urinary Diversion
Complications of Extracorporeal Shock Wave Lithotripsy
Complications of Pediatric Urinary Diversions and Bladder Augmentation
Complications of Urethral Reconstruction
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
