The Geriatric Patient
Geriatric patients, or “older adults,” are defined chronologically as 65 years and older. They represent a growing percentage not only of our adult patient population but also of those requiring critical care–level interventions within the emergency department (ED). Between 2000 and 2010, the population 65 years and older increased at a faster rate (15.1% over a 10-year period) than the U.S. population as a whole (9.7% over a 10-year period) and currently represents over 13% of the total U.S. population. There was a concomitant increase in persons 85 years and older by a remarkable 29.6% over the same time frame. The older adult population is expected to double to more than 70 million by 2030.1 A recent retrospective cohort study in the United States showed that older adult patients represent 45.7% of the total intensive care unit (ICU) population (with 10.35% of all patients being over 85 years old).2 An analysis of over 120,000 ICU patients in Australia and New Zealand demonstrated that 13% of ICU admissions were for patients over 80 years old, with an annual increase in ICU admission in this population of 5.6% per year.3
The baseline health and functioning of older adults is improving, as advances in education have yielded changes in lifestyle with respect to diet, exercise, and preventative care. In addition, improvements in pharmacotherapy and health-related technology are enabling this population to live longer and better. With better resources and more effective goal-directed therapy, our ability to resuscitate and care for very sick older adults has also greatly improved, as have clinical outcomes in this population.4 Age alone, therefore, should no longer be the deciding factor when formulating plans of care for critically ill geriatric patients. Rather, it should be a combination of the severity of the acute medical issue, the biologic and physiologic state of the patient, and the patient’s wishes.
GENERAL APPROACH TO THE OLDER ADULTS
The reality of aging is that all persons experience approximately a 1% per year decline in physiologic functioning after age 30.5,6 However, everyone starts at a different baseline. There are two ways to quantify age: biologic age (physiologic age), often associated with frailty, poor biologic reserve, or impairment of several biologic systems,4 and chronologic age.7 The literature differs over whether advanced age should be considered an independent risk factor for mortality,2,3,8 but several authors have emphasized that advanced age alone does not preclude a successful ICU outcome.9–12 Aspects of particular importance in surviving critical illness that may be independent of chronologic age include overall physiologic reserve, organ structure and function (e.g., cardiac or renal), pulmonary compliance and vital capacity, and changes in volume of distribution that occur with changes in body composition. Each of these is discussed further in the sections below.
The emergency physician should be cognizant of the following common themes in the management of older adults.
1.Polypharmacy is widely prevalent and represents a serious hazard to this population. The decreased functional reserve of major organ systems increases the risk of decompensation in response to certain medications, particularly those affecting the cardiovascular and renal system. Drugs with hepatic clearance, such as diazepam, can also cause significant harm. When considering medical therapy, the mantra “start low and go slow” is well advised in the geriatric population.13
2.Atypical presentations are the rule, not the exception, in medical, surgical, and trauma patients. While this text does not focus on trauma, clinicians should maintain a high index of suspicion for severe traumatic injuries with even the most minor of mechanisms, such as a fall from standing height. Geriatric patients are more susceptible to intracranial hemorrhage, fractures, and their associated complications, with increased risk for bleeding diatheses given the prevalence of anticoagulant and antiplatelet use. Among patients older than 85 years, trauma is the second most common cause for ICU admission following cardiovascular diagnoses.2
With these caveats in mind, the following sections review acute presentations in older adults that require special consideration.
Severe sepsis continues to carry a high mortality rate despite advances in early detection and goal-directed therapy.14 Older adults have decreased physiologic reserve, undergo immune system senescence, and are more likely to have multiple comorbidities. It follows that the incidence of sepsis is higher in older adults and that age is an independent predictor of mortality. Older adults have a relative risk of sepsis of 13.1 compared with younger patients.15 The mortality rate for patients >65 years is 27.7% and close to 40% for those over 85 years.15 Pneumonia is the most common culprit for infection, followed by urinary tract infections and then bacteremia.15 Thus, the workup for these patients should always include a chest radiograph, urinalysis, urine culture, and blood cultures; this is true even if a fever is not documented, since a blunted or absent fever response is common in older patients.
As with all patients, early antibiotic coverage is essential, with mortality increasing each hour treatment is delayed.16 This population is also more susceptible to drug-resistant organisms, as their tendency toward infection leads to frequent antibiotic use, both as outpatients and as inpatients.17 The following are important considerations when choosing an appropriate antibiotic regimen:
1.Is the patient coming from a nursing home or rehabilitation center?
2.What infections has the patient previously had, and what were the sensitivities on prior cultures?
3.Based on the presentation and exam, what is the most likely source of the infection? (Remember: these patients present atypically)
4.What are the local/regional resistance patterns, including those at the local nursing homes and neighboring communities?
In the absence of specific microbial data indicating a history of resistant organisms, the initial antibiotic regimen should be broad spectrum and then narrowed once further clinical data and culture sensitivities are obtained.
Early goal-directed therapy (EGDT) and aggressive fluid resuscitation have become a mainstay of sepsis therapy.18 The mean age of the 263 patients included in the EGDT study was 65.7 years (SD 17.2); however, there was no subgroup analysis performed on those patients 65 years and older. To our knowledge, there have been no further studies that specifically explore the use of EGDT in this population. Thus, older adults should receive aggressive fluid resuscitation (a minimum of 30 mL/kg)19 when indicated based on sepsis markers. As this population has a higher rate of heart failure and, therefore, has difficulty managing fluid balance, the clinician should perform frequent patient reassessments during fluid infusion, paying particular attention to respiratory status.
The use of vasopressors in the older adult population has not been extensively studied. Important factors to consider when deciding to initiate vasopressor support include this group’s increased incidence of heart failure and potential need for inotropic support. Confounding this picture is that one-third of heart failure in older patients is primarily diastolic, resulting from impaired ventricular relaxation. These patients are particularly dependent on late diastolic filling in order to maintain adequate preload. As this late-phase filling is provided by atrial contraction, adequate rate control is essential in order to avoid pulmonary congestion. Rate control in a tachycardic patient, however, should not be initiated until initial, yet judicious fluid resuscitation has occurred, as an elevated heart rate is often a necessary compensatory mechanism. When choosing a rate-controlling agent, it is important to remember that as one ages, cardiac output declines and the heart increasingly relies on endogenous catecholamines for inotropic support. Because of this, beta-blocker agents can place older adult patients at greater risk of acute pulmonary edema, and many emergency physicians are therefore more comfortable using calcium channel blockers as the initial rate-controlling agent.
The use of corticosteroids has also not been specifically studied in the older adult population. Studies supporting the use of steroids, including the CORTICUS trial,20 had a mean patient age of 60.8 years, with 79% of the patients younger than 75, making it difficult to generalize findings to the older adult population.14
Abdominal pain is a common presenting complaint in the older adult population. As with other illness, significant abdominal pathology in older adults frequently presents atypically, often without localizing signs on exam and therefore requires comprehensive evaluation with advanced imaging. Of older adults presenting with abdominal pain to the ED, approximately 60% will be admitted, and close to 20% will require invasive procedures or surgery. Approximately 14% of patients with abdominal pain discharged home from the ED, as well as 9% of those discharged from inpatient admissions for abdominal pain, will return to the ED within 2 weeks of the index visit, with a nearly 5% mortality rate if admitted or readmitted to the hospital.21 Moreover, patients aged 75 years and older are less likely to have an ED diagnosis that is concordant with the final diagnosis than patients who are younger (76% vs. 87%).21 It is important to remember that diseases such as appendicitis and cholecystitis have a bimodal distribution, with a significant percentage occurring in older adults (14% and 12% to 41%, respectively).22–24
With advanced age, the heart undergoes structural changes—including left ventricular (LV) wall thickening, left atrial and LV cavity dilation, and coronary artery wall thickening—that together result in decreased LV relaxation and diminished functional cardiac reserve. As a result of these changes, the older adult patient typically will have a higher resting systolic blood pressure, decreased intrinsic sinus rate, and increased sympathetic activity but with decreased response to beta-adrenergic stimulation. On electrocardiogram, clinicians will most often find nonspecific ST or T wave changes, decreased QRS voltage, increased ectopic beats, lengthening of the intervals, and bundle branch blocks.
With our aging population, patients admitted to the ICU more frequently demonstrate evidence of these changes in cardiac function, including an increased incidence of heart failure, cardiac arrhythmia, and valvular heart disease. The aging population, conversely, confers a reduced prevalence of diabetic complications, alcohol abuse, chronic obstructive pulmonary disease (COPD), and liver failure.2 A retrospective cohort study of 1,409 patients confirmed that cardiac patients are the most common ICU admission group in patients >65 years (67.7%), with acute coronary syndrome (ACS) being the most frequent diagnosis (76.7%).4 A separate study showed that having a cardiac diagnosis on admission correlates significantly with an increased mortality risk.8
Congestive heart failure (CHF) is the most common principal diagnosis among all hospital admissions in older adults. In 2009, CHF accounted for 149 hospital stays per 10,000 population among all adults aged 65 to 84 years and for 433 stays per 10,000 population among all adults aged 85 years and older.25 As an individual ages, the decreased elasticity of the great vessels leads to increased afterload, causing LV hypertrophy, increased coronary artery oxygen consumption, and possible ischemia. Increased afterload is compounded by chronically impaired renal flow, which leads to afferent vasoconstriction and increased fluid retention, exacerbating already compromised cardiac function.26
Of note, a CHF patient’s ejection fraction, a value often ascertained in the ED through chart review or bedside echocardiography, is frequently normal or even increased. It has been shown that as many as 30% to 50% of heart failure patients have circulatory congestion on the basis of diastolic dysfunction, with impaired ventricular relaxation causing higher LV filling pressures and reduced left ventricular end diastolic pressure (LVEDP).27,28 This diastolic failure often requires a clinical approach that focuses on afterload reduction while remaining cognizant of the risk of overdiuresis, as is discussed below.
Because CHF is primarily a clinical diagnosis, pertinent findings on a physical exam, including lower extremity edema and crackles in the lung bases, are important to identify. Depending on the degree of heart failure, the patient will present with varying levels of dyspnea, fatigue, and/or orthopnea. In the setting of severe hypoxia, an older adult patient may also present with atypical symptoms including somnolence, confusion, and failure to thrive.
The causes of exacerbations of heart failure in older adults are myriad. Medication and dietary nonadherence are most common, followed by arrhythmias, cardiac ischemia, renal failure, pulmonary embolisms, uncontrolled hypertension, adverse effects of medications, and infection.26 The key to management beyond the initial presentation is identifying the underlying precipitant. B-type natriuretic peptide (BNP) is a common marker for CHF (90% sensitive, 76% specific); however, plasma BNP levels have been shown to increase with age independent of ejection fraction, decreasing specificity.29 Other important diagnostic laboratory values include hemoglobin (anemia is an independent prognostic factor in elderly), electrolytes (in particular, hypokalemia from diuretic use), and troponin, which, along with an ECG, is needed to exclude ischemia as a precipitating cause. Chest radiograph and echocardiography can help confirm the diagnosis.
All patients presenting in acute pulmonary edema require immediate intervention. Following assessment and stabilization of the ABCs, first-line therapy includes supplemental oxygen and nitrates. However, when initiating medical therapy for CHF in an older adult, the emergency physician must proceed with an appreciation of the cardiovascular changes that can occur with age. For example, extra care must be taken in patients with severe aortic stenosis (AS), as nitrates can cause an acute and severe drop in blood pressure. It is also imperative to ask patients if they recently have taken Viagra or any other phosphodiesterase type-5 inhibitor, as this combination may also result in rapid hypotension. Intravenous ACE inhibitor (enalaprilat) is an alternative option if nitrates are contraindicated but is used more commonly in chronic management.30 Diuretics are also effective in the setting of frank volume overload; however, care must be taken not to over diurese and potentially compromise perfusion. Fortunately, in most cases of decompensated heart failure, it is the accompanying sympathetic surge—not a sudden volume overload—that is the primary cause of pulmonary decompensation. Equally challenging are patients with diastolic heart failure who are preload dependent and thus require higher filling pressures due to a stiff LV. As such, if not carefully managed, these patients—following aggressive nitrate and diuretic therapy—can decompensate due to a lack of forward flow. Noninvasive positive pressure ventilation (NIPPV) reduces intubation rates in this population and is discussed further in the next section.
ACS complicated by cardiogenic shock occurs in 5% to 7% of all adult patients with an associated mortality rate >50%.31 The mortality rate is higher for elderly patients with ACS than for younger patients; however, percutaneous coronary intervention (PCI) appears to provide better long-term survival and quality of life (defined by return to good functional status) for older adults receiving the therapy than for those who do not.32 For geriatric patients presenting in cardiogenic shock, inotropic assistance may be needed. Dobutamine (beta-1 agonist) and milrinone (phosphodiesterase inhibitor) are the drugs of choice. While emergency physicians have been traditionally more comfortable using dobutamine in the ED setting, it carries a greater risk of ventricular ectopy and tachycardia when compared to phosphodiesterase inhibitors.33
Admission to hospitals for cardiac arrhythmias increased by 25% in adults aged 85 years old and above between 1997 and 2009.25 As people age, there is a stretching and fatiguing of the conduction system, which leads to ectopic beats and altered paths of depolarization. These patients present with a range of symptoms and degree of hemodynamic compromise, which dictates how quickly the emergency physician must act and which strategies are most appropriate. Management beyond the initial resuscitation—which focuses on identifying the underlying etiology of the arrhythmia—requires an appreciation of cardiac and vascular changes that occur in the aging population.
Atrial fibrillation (AF) is the most common sustained arrhythmia in older adults, with a prevalence of 5% and an incidence that doubles with each decade of life.34 AF leads to 20% of all stroke-related deaths.35 Acute management of AF with rapid ventricular rate is dictated by the patient’s hemodynamic state. If the patient is hypotensive or unstable, immediate cardioversion is required and safe in the elderly, with similar success and complication rates to that of the younger population.36 Cardioversion for those patients with stable, new-onset AF can also be effective (see Chapter 17).
If the patient is symptomatic and normotensive, rate-controlling agents should be utilized along with anticoagulation. Given the prevalence of heart failure as previously discussed, the emergency physician should presume an abnormal EF if no information is known. Emergency physicians will often use diltiazem, which is a good choice in older adults as it can be titrated with small boluses followed by a drip, allowing for close monitoring of potential hemodynamic compromise. Based on experience with this population, consensus recommendation is to start with 10 mg IV diltiazem and titrate, rather than the recommended 0.25 mg/kg. Amiodarone is the preferred drug in known impaired cardiac function as it causes less hypotension37; however, it is harder to titrate. Digoxin is another option for rate control, but its onset of action is significantly delayed and thus not ideal for use in the ED setting. In patients with known normal EF, beta-blockers and verapamil may also be considered. However, verapamil can have altered pharmacokinetics in the elderly due to reliance on hepatic metabolism38 and therefore should be used cautiously.
If a patient with rapid AF is asymptomatic, the emergency physician has time to investigate the etiology, such as noncompliance with home medications or any of the myriad pathologic causes/triggers of AF. Slowing a patient in AF too quickly may be ill advised if the patient’s rate is an appropriate response to an underlying condition such as dehydration, fever, or infection. Administration of intravenous fluids, antibiotics, and antipyretics may lower the heart rate while treating the inciting cause.
Given the prevalence of conduction disease in older adults, sick sinus syndrome and complete heart block are more common in this population and should be considered in any patient with cardiac instability. A 12-lead electrocardiogram is essential for any patient with arrhythmia or derangement in vital signs.
OTHER CARDIAC CONSIDERATIONS
AS affects nearly 10% of patients over 80 years and is the third most common cause of cardiac death.39 Symptomatic AS, which often presents in the setting of ACS, acute decompensated heart failure, or syncope, requires treatment that provides necessary afterload reduction while maintaining adequate preload. Nitrates and diuretics should be used judiciously. Aortic valvuloplasty or replacement (AVR) is the definitive treatment for severe AS. Recent studies have shown favorable survival in patients >80 years of age (>50% surviving 6 years) after AVR, with concomitant coronary artery bypass grafting not changing the mean survival rates.39,40
Acute Coronary Syndrome
ACS is common in this age group, and older adults with an acute myocardial infarction have a higher mortality risk. Atypical presentations of ACS are commonplace in older adults; over 50% of this population’s myocardial infarctions will present without chest pain, or “silent.”41 The differences between men and women in presentation and mortality attenuate with increasing age. There are significant data now showing that fibrinolysis, PCI, and CABG should be considered in even the very old.31,40,42–44
The management of respiratory failure in older adults is multifaceted and requires consideration of patient acuity, resource utilization, and the degree of invasiveness of potential interventions. The decision to implement mechanical ventilation can be complex, especially in very chronologically old patients.45 Studies suggest that age is an independent risk factor for mortality in the setting of mechanical ventilation.46,47 However, evidence regarding the role of pulmonary physiology—independent of age—is more compelling.
Age-related changes in pulmonary physiology result in a decline in overall patient functioning.48 Decreased lung compliance and stiffening of costovertebral joint articulations and associated muscles, including the diaphragm, lead to increased risk of complications from mechanical ventilation. There is an increased propensity toward distal airway collapse, with a subsequent decrease in lung surface area, gas exchange, and lung capacity. Reduced peripheral carbon dioxide sensitivity decreases the hypoxic drive and ventilatory response, often most pronounced during sleep. Because of these physiologic impairments, older adults are more likely to develop chronic respiratory failure when recovering from an acute pulmonary illness.
An ARDS network subgroup analysis showed that patients older than 70 years who require endotracheal intubation and mechanical ventilation have an equally effective response to low tidal volume ventilation, despite increased mortality.49 Further data are needed to determine appropriate ventilatory strategies in older adults, given their higher rates of COPD and primary lung conditions.14
NIPPV has an important role in treating mild to moderate respiratory distress in older adults.48,50 In both younger and older patients, NIPPV is associated with overall less discomfort, fewer complications, and better short-term results than endotracheal ventilation for specific disease processes, described below. NIPPV promotes muscle rest and improves gas exchange by increasing alveolar recruitment and lung volume. The ability of the patient to protect his or her airway is always a concern with NIPPV, especially in older adults with comorbid conditions. Dementia alone should not preclude the use of NIPPV; agitated delirium, however, may limit its use.51
NIPPV can be helpful in the management of the following illnesses:
- Acute exacerbation of COPD: The success rate of NIPPV in the older adult population is similar to that in the general population.52 A positive response to NIPPV is defined by improved acidosis, a lower respiratory rate, and decreased hypercapnia, all within 1 to 2 hours (with a maximum response period of up to 4 hours) before additional ventilatory support is needed.51,52
- Acute cardiogenic pulmonary edema: NIPPV (CPAP in particular) has been shown to improve gas exchange, normalize hemodynamics, and decrease rates of intubation.53 It should be used with caution in patients with active cardiac ischemic or acute myocardial infarction, as it can increase oxygen demand by coronary arteries, worsening ischemia.48,54
- Pneumonia (leading infectious cause of death in this age group): NIPPV use is controversial. Limited data suggest NIPPV may be helpful in patients with underlying COPD.48
- End-of-life scenarios: Consider NIPPV, as it can serve as a palliative measure.
Based on findings from the studies above, if no significant improvement is achieved within 2 hours of NIPPV, endotracheal intubation and ventilation should to be considered in older adults, especially if a reversible condition is causing acute respiratory failure.51
DELIRIUM AND AGITATION
Delirium, or an acute change in mental status not caused by underlying dementia, is an often underappreciated consequence of both critical illness and the hospital environment.55 It is an emergency unto itself, with an in-hospital mortality rate mirroring that of sepsis or acute myocardial infarction.56 The older adult population is especially at risk of delirium and can present with either a hypoactive (i.e., somnolent, lethargic, stuporous, etc.) or hyperactive (i.e., agitated, etc.) state (discussed in detail below).57
Identifying delirium is the first challenge for the emergency physician, especially when the patient’s degree of underlying cognitive impairment is unknown. The Confusion Assessment Method (CAM)58 is the most commonly used tool in critical care settings59 and is the only validated tool for the ED (86% sensitivity, 100% specificity).60 The CAM evaluates four elements: (1) acute onset and fluctuating course, (2) inattention, (3) disorganized thinking, and (4) altered level of consciousness. A patient must demonstrate elements 1 and 2 as well as either 3 or 4 to be considered “delirious.”58 The CAM-ICU scale has the potential to be even more applicable in the ED, once validated.57
Older adults experience physiologic changes that alter both pharmacokinetics and pharmacodynamics, predisposing them to delirium. Changes in drug distribution (pharmacokinetics) occur due to relatively higher fat stores as compared to lean muscle mass. This increases the absorption of lipophilic drugs and imparts a longer half-life (e.g., propofol, diazepam, midazolam). The lower percentage of muscle mass in an older adult’s body decreases the absorption of hydrophilic drugs (e.g., digoxin, theophylline), thereby lowering their effective half-life but raising their peak plasma concentrations and therefore toxicity risk.38 Older adults are also more likely to have decreased gastrointestinal first-pass metabolism, hepatic metabolism and clearance, and renal clearance. Acute renal failure is also more common in the elderly population,14 and multiple commonly prescribed drugs—including digoxin, enoxaparin, dabigatran, metformin, lithium, and Parkinson medications such as amantadine—may cause toxicity in this clinical setting. Finally, aging also effects neurohormonal receptors, especially adrenergic receptors, which can alter a drug’s effects on the body (pharmacodynamics); however, inadequate evidence exists to provide specific recommendations regarding this process.14 Medication dosing decisions should take into account the pharmacokinetics and pharmacodynamics of each drug as well as the patient’s underlying physiologic functioning.
Delirium has three clinical subtypes: hyperactive, hypoactive, or mixed type. Hyperactive (or agitated) delirium can make evaluation of the underlying precipitant challenging for the emergency physician. Once a patient has been identified as delirious, the next step is the evaluation of the delirium precipitant. Certain causes are often overlooked, yet are more readily reversible than the traditionally considered life-threatening causes, such as infection, stroke, MI, hypoglycemia, and underlying cognitive impairment. These less frequently considered causes include inadequate pain control, urinary retention, constipation, dehydration, polypharmacy, and environmental precipitants in the patient’s immediate surrounding.57
Delirium can be managed with both nonpharmacologic (preferred) and pharmacologic interventions, although the literature reveals no current standard of practice. Nonpharmacologic strategies include decreasing sensory stimulation, keeping family (or familiar faces) at the bedside or utilizing one to one observation, and choosing a calmer and quieter location for the patient, preferentially by a window, to maintain orientation. Pharmacologic interventions should be reserved for emergencies; in other words, when patient or provider safety is of concern, or if the patient’s agitation is impeding the necessary medical care. Benzodiazepines should be avoided, especially as monotherapy, as they may worsen delirium (discussed in detail in Chapter 56). If necessary for minimal sedation, lorazepam is preferred over diazepam because of how they are metabolized in the liver. Haloperidol, a typical antipsychotic, has been the traditional drug of choice in the treatment of delirium, with a prolonged QT interval being the only significant contraindication. Currently, however, the atypical antipsychotics, such as olanzapine, quetiapine, and risperidone, are increasingly used in the management of delirium. Each of these antipsychotic options, however, has limitations, and familiarity with their side effect/safety profiles is necessary. Despite several studies involving atypical antipsychotics, there is no clear evidence to date on the efficacy and safety profile of these drugs for use in managing agitated delirium in the elderly.
Admissions to the hospital in general, and ICUs in particular, are increasing more rapidly than our resources can sustain. More than any other demographic, the older adult population is contributing to this complex problem.3 ICU triage is known to be a subjective process, and literature demonstrates age-discriminatory practices, especially when resources are scarce.61,62 These age-biased practices are supported by studies showing that patients over 80 years of age have lower short-term survival rates, modified by prehospital function, comorbid illness, surgical status, primary diagnosis, and illness severity. Survivors in this age group are more likely to go to rehab or long-term care facilities.3
After correcting for disease severity, however, elderly patients have the greatest mortality benefit when receiving ICU-level care. The older adult patients who are deemed “too well” for the ICU and diverted to lower levels of care suffer the greatest loss. Limited physiologic reserve increases their vulnerability to disease processes. Receiving care in a setting that makes early recognition of decompensation possible has a marked effect on their clinical outcomes.63 Emergency physicians should advocate for older patients to be triaged to the ICU whenever warranted. Until we have a more reliable way to predict prognosis, these patients need to be treated aggressively, unless their wishes are otherwise.
While the ED will continue to send critically ill older adults to the ICU, the emergency physician can also work to help avert many of the conditions that lead to these admissions. Preventable illnesses such as falls and gastrointestinal bleeds are a source of many ICU admissions in the elderly, especially in individuals over 80 years of age and with the advent of novel anticoagulants. Emergency physicians on the front lines of care for these patients can coordinate preventative measures as part of their purview of care. Good discharge planning and medication reconciliation upon discharge is essential and can help minimize return visits and new illnesses by working to ensure a safer home environment and more coordinated primary care.
CI, confidence interval; OR, odds ratio; RR, relative risk.