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Journal of Korean Academy of Nursing (2002) Vol. 32, No. 7 Anxiety after Acute Myocardial Infarction and In-Hospital Complications Kyungeh An, PhD, RN Purpose of the study. A retrospective and descriptive survey was conducted to investigate the level of anxiety that patients experience in early stage of AMI and to examine whether anxiety independently predict inhospital complications. Significance of the study. AMI is a major cause of death and disability. Anxiety may contribute to developing complications and mortality. However, the association between anxiety and complications has not been examined. Results. Data were analyzed for 424 AMI patients enrolled for MICA (Myocardial Infarotion Complication and Anxiety) project. The mean score of the state anxiety inventory (SAI) measured within 72 hours after admission for the whole sample was 39.14 (±12.77) and ranged from 18 to 80. Overall, 161 patients (38.0%) experienced at least one episode of in-hospital complication (i.e. VT, VF, reinfarction, recurrent ischemia or cardiac death). Incidence of in-hospital complications was higher in the high anxiety group than in the low anxiety group (45.4% vs. 31.2%). There were significant differences in the incidence of recurrent ischemia between groups with low level of anxiety and high level of anxiety (27.5% vs. 18.9%). According to the Ward criterion from the logistic regression, anxiety reliably predicted the occurrence of in-hospital complications. Anxiety (odds ratio = 1.75, 95% CI 1.01-3.01, p= 0.04) significantly contributed to the model. Patients who were in the high anxiety group were 1.8 times more likely to have in-hospital complications than those who were in the low anxiety group. Conclusion and suggestions. This finding confirms that patients experience significant level of anxiety early after AMI, and this anxiety, after controlling other risk factors for the complications, is a reliable predictor of in-hospital complications. Key Words: anxiety, acute myocardial infarction, in-hospital complications INTRODUCTION Acute myocardial infarction (AMI) is defined as irreversible necrosis of myocardial tissue caused by inadequate blood flow to the myocardium for a critical period of time (Vincent, 1994). Patients who experience AMI inevitably experience anxiety. Anxiety is defined as a feeling of fear, tension, panic or the expectancy that something unpleasant is going to happen and is almost invariably accompanied by physical signs and symptoms (Medalie & Goldbourt, 1976). Anxiety develops early after AMI, continues into the recovery phase and influences the prognosis of the disease (Malan, 1992; Stern, 1984). Although anxiety is expected to some degrees in all AMI patients (Stern, 1987), it can be debilitating to many patients (Krantz, 1980). If severe and untreated, 1. Ewha Womans University, College of Nursing Science Corresponding author: Kyungeh An, PhD, RN, Ewha Woman’ s University, College of Nursing Science 11-1 Daehyun-dong, Seodaemun-gu, Seoul 120-750, Korea Tel: 82-2-3277-3926 Fax: 82-2-3277-2850 Received August 6, 2002 ; Accepted December 5, 2002Januar 31, 2000 1000 Journal of Korean Academy of Nursing Vol. 32, No. 7 anxiety may contribute to fatal cardiac events by exaggerating sympathetic activity (Krantz, Helmers, Nebel, Gottniener, & Rosanski, 1990; Larson, Schneiderman, & Pasin, 1986; Lown & Desilva, 1978; Lown et al., 1980). Exaggerated sympathetic activity increases circulating catecholamines and results in cardiovascular over-reactivity. Cardiovascular reactivity often results in tachycardia and increases systemic vascular resistance. Sympathetic hyperactivity also increases the risk of ventricular arrhythmias, cause myocardial ischemia by increasing oxygen consumption, and increase left ventricular afterload by producing systemic vasoconstriction (Swan, 1991). A previous study found that anxiety early after AMI independently predicted in-hospital complications such as ischemic and arrhythmic events (Moser & Dracup, 1996). In the clinical setting, however, both assessment and treatment of anxiety tend to be undervalued. This is partially because the physical symptoms of anxiety are often masked by the symptoms of cardiac disease such as chest pain, shortness of breath, rapid pulse, elevated blood pressure, and palpitations. In addition, lack of health care providers’ awareness of the physiologic consequences of anxiety may contribute to its under-treatment. The vast majority of investigators who conducted anxiety research with AMI patients focused on the anxiety after discharge from the hospital. Only a limited number of investigators paid attention to the anxiety early after AMI and its potential physiological effects on the development of in-hospital complications (Boogaard, 1984; Moser & Dracup, 1996; Hillers, 1994; Stern, 1976). Increasing evidence suggests that anxiety early after AMI plays a significant adverse role in AMI recovery (Bloch & Maeder, 1975; Booth-Kewley, & Friedman, 1987; Brown & Mumford, 1984; Byrne & Whyte, 1983; Hacket & Cassem, 1984; Moser & Dracup, 1996). Moreover, most investigators of these studies measured anxiety several days and weeks after AMI, and missed the peak level of anxiety early after AMI (Boogaard, 1984; Hillers, 1994; Stern, 1976). Assessing anxiety in early stages of AMI that includes the time of peak anxiety is critical for understanding the significance of anxiety. Furthermore, examining the relationship between anxiety and in-hospital complications is also important to prevent in-hospital complications and early mortality from AMI. There is lacking of data based on clinical research that supports the negative effects of anxiety on prognosis of AMI. Therefore, research studies that investigate anxiety early after AMI and examine the effects of anxiety on development of in-hospital complications are needed. The purposes of this study were to investigate the level of anxiety that patients experience in early stage of AMI, and to examine whether anxiety independently predict in-hospital complications. Findings from this study will call more attention of clinicians to the importance of assessing and treating patients’ anxiety during the early stage of AMI. Specific aims of this study were as follows: (1) Describe the anxiety level patients experienced during 72 hours of their arrival at the hospital. (2) Compare in-hospital complications between two groups experienced low vs. high level of anxiety. (3) Test the significance of anxiety after controlling traditionally known risk factors that predict in-hospital complications. METHODS 1. Research Design A retrospective and descriptive survey was conducted. 2. Subjects Patients who were admitted to coronary care units and met the following criteria were eligible for the study: (1) diagnosis of AMI confirmed by elevated cardiac enzymes (i.e. CK and CK-MB, or troponin) and typical EKG changes; (2) free of cognitive impairment that might interfere with ability to participate in a 15-20 minute interview (3) free of non-cardiac serious or life threatening comorbidities such as sepsis, stroke, or acute renal failure. Patients were excluded if they suffered a peri-procedural MI because they might experience psychological distress in a different pattern. For patients who were waiting for major diagnostic or treatment procedures such as cardiac catheterization, the interview was postponed because the anxiety caused by impending procedures could confound the anxiety following AMI. Four hundred twenty four AMI patients were enrolled in this study, including 281 men and 143 women. A sample size of 400 was originally planned based on the following information: (1) medium effect size for the association between anxiety and in-hospital complications; (2) α=0.05; and (3) power=0.80; (4) expected in-hospital An Anxiety and MI Complications 1001 complication rate of 25% (Moser & Dracup, 1996). Data were colleded from September 1996 to September 1999. ranged from .86 to .95 by means of Kuder-Richardson 20 formula. The Chronbach’s α· was 0.94 in this sample. 5. Data Analysis 3. Procedures Structured interview was conducted to obtain data in coronary care units of five large urban university medical centers and two large private hospitals in the United States and one private hospital in Australia. Data were consisted of socio-demographic data, clinical information, and anxiety assessment. Socio-demographic data included gender, age, marital status, work status, yearly income, and education level. Clinical data were obtained from the medical record review. Clinical data included the presence of comorbidities, information about diagnostic procedures and about the major medical and surgical treatment that the patient received during the hospitalization. Comorbidities included history of hypertension, diabetes, previous myocardial infarction, angina; and coronary artery disease without prior coronary events. Diagnostic procedures included cardiac catheterization and/or echocardiogram, insertion of Swan Ganz catheter or central venous pressure line or arterial pressure line. Therapeutic procedures include major medical and surgical treatments. Medical treatment refers to medication for the treatment of AMI such as primary thrombolytic therapy, use of βblockers and supportive medication for pain and anxiety use of ventilator, and insertion of intra-aortic balloon pump, cardioversion and defibrillation. Surgical treatments include insertion of temporary pacemaker, percutaneous transmural coronary angiography with or without stent, and coronary artery bypass grafting (CABG) surgery. 4. Instrument State anxiety was measured by the state anxiety inventory (SAI) subscale of the State-Trait Anxiety Inventory (STAI) (Speilberger, 1983). The SAI is a widely used and well established instrument for both psychiatric patients and medically ill patients. The SAI consists of 20 statements that are rated by patients on a 4-point rating scale. Responses range from “not at all (1)” to “very much so (4)” as patients rate how they feel at the current time. Item scores are summarized, scores on the instrument range from 20 to 80, and higher scores indicate higher levels of anxiety. Webb and Riggin (1994) reported that reliability Data were analyzed using SPSS 9.0-PC. To describe the level of anxiety that patients experienced in early stage of AMI, descriptive statistics were used. Independent t-test was conducted to compare the incidence of in-hospital complications between the groups with low and high level of anxiety. A multiple logistic regression was conducted to examine whether anxiety early after AMI can predict in-hospital complications after controlling other physiologic risk factors. RESULTS 1. Socio-demographic and clinical data Data were analyzed for 424 subjects who included 281 (66.3%) men and 143 (33.7%) women. The sociodemographic characteristics of the entire sample are summarized in Table 1. The mean age of the sample was 62(± 13) years and ranged from 24 to 92 years. The mean years of education was 13 (±3). Approximately 68.2% of the sample were married, and 38% had less than $20,000 annual income. Clinical characteristics of the sample are summarized in Table 2. Clinical characteristics included Killip classification at the time of admission, type and location of infarction, systolic and diastolic blood pressure and pulse rate at the time of admission, peak level of cardiac enzymes, peak level of chest pain reported by patients, and left ventricular ejection fraction. Table 1. Sociodemographic Characteristics of Sample Sociodemographic Characteristics N (%) Marital Status Married Single* Widowed 289 (68.2) 074 (17.5) 061 (14.4) Yearly Income <$5,000 $5,000-$20,000 $20,000-$40,000 $40,000-$60,000 >$60,000 17 (4.5) 124 (33.2) 114 (30.5) 069 (18.4) 050 (13.4) Characteristics (Valid N) Mean±SD Age in years (426) Education in years (415) 62±13 13±30 *Single represented single, divorced, separated, and cohabitant 1002 Journal of Korean Academy of Nursing Vol. 32, No. 7 Most of subjects (93.3%) were in either Killip Class I or II with 258 (60.8%) fulfilling criteria for Killip Class I, indicating no signs or symptoms of left ventricular dysfunction, and 137 (32.5%) fulfilling criteria for Class II, indicating mild to moderate failure. Only 27 subjects (6.4%) fulfilled criteria for class III indicating pulmonary edema. One subject was admitted (.2%) in class IV indicating cardiogenic shock. Regarding type of AMI, 251 (60.9%) subjects had Qwave infarction and 161 (39.1%) had non Q-wave infarction. The two most frequent locations of infarction were inferior (51.6%) and anterior (41.5%). Mean blood pressure of the sample was 142±29/81±19 and the pulse rate was 79±20. The mean score of the subjects for perceived level of chest pain reported by patients using a 0 to 10 scale (0 means no pain, 10 means the worst pain ever experienced) was 6.91±2.54. Data about the comorbidities of diabetes, hypertension, history of smoking, previous infarction, angina, and other coronary artery disease in men and women are summarized in Table 3. Hypertension was present in 248 (58.8%) subjects and diabetes was present in 93 (22.0%) subjects. In this sample, 35.6% of the subjects were current smokers at the time of infarction. Twenty eight percent of subjects experienced previous AMI and 2. Level of anxiety patients experienced during 72 hours of their arrival at the hospital Table 2. Clinical characteristics of the sample Clinical Characteristics (Valid N) N (%) Killip Classification (N=421) Killip class I Killip class II Killip class III Killip class IV Type of MI (N=412) Q-wave Non Q-wave 251 (60.9) 161 (39.1) Location of MI by EKG (N=376) Anterior Infarction Inferior infarction Posterior infarction Lateral infarction 156 (41.5) 195 (51.9) 057 (15.2) 077 (20.5) Apical infarction Systolic blood pressure (mmHg) Diastolic blood pressure (mmHg) Pulse rate (beat/mm) Peak CPK (U/L) Peak CKMB (ng/ml) Peak Troponin (ng/ml) Peak chest pain (0-10) LVEF (%) 37% of the subjects experienced previous angina. Previously known coronary artery disease without a cardiac event was identified in approximately 19% of the subjects. In this sample, 32.6% of AMI patients had thrombolytic therapy in the emergency department. Among these, 28.5% received t-PA (tissue plasminogen activator) and 4.8% received Streptokinase. Nitrates were the most frequently given medication to the subjects in the emergency department (89%). Heparin was given to 85.9% of the sample and acetyl salicylic acid (ASA) was given to 81.9% of the sample. Beta-blockers were given to 53% of the sample. Anxiolytics were given to 32.1% of the subjects. Twenty four percent of the subjects had primary percutaneous transluminal coronary angioplasty (PTCA) as an initial treatment. Data related to the treatment and procedures in the CCU are summarized as following. Beta-blockers, lidocaine either for prophylactic purpose or in response to arrhythmias, calcium channel blockers, digitalis, inotropes, heparin, ace-inhibitors, and nitrates were used. Overall, 349 (83.3%) patients had cardiac catheterization. Among these, 266 (63.5%) patients had PTCA and 217 (52.0%) received a stent. 256 (60.8) 137 (32.5) 27 (6.4) 01 (0.2) 12 (3.2) Mean±SD 142±29 081±19 079±20 1281.92±1391.67 140.44±156.64 063.58±193.86 6.91±2.54 51.16±12.22 The mean score of the SAI for the whole sample was 39.14±12.77 and ranged from 18 to 80. Women reported higher level of anxiety than men (42.03±12.86 vs. 37.74±12.51) (t=-3.30, df=421, p<0.001). Age had a significant effect on the anxiety score: F (2, 481) = 5.258, p= 0.022. Marital status: F (2, 421)=3.774, p=0.024; use of ASA in the emergency department: F(1, 418) = 9.147, p= 0.003; use of anxiolytics in the emergency department: F (1, 413)=22.418, p<0.001; and use of IV nitrate in the CCU : F(1, 409)= Table 3. Comorbidities and History of Heart Disease Comorbidity & History of Heart Disease (Valid N) Hypertension (422) Diabetes Mellitus (N=423) Smoking (N=424) Previous MI (N=424) Previous angina (N=418) Previous CABG (N=424) PTCA (N=424) Previous Stent (N=424) History of known CAD without events (N=423) N (%) 248 (58.8) 093 (22.0) 151 (35.6) 120 (28.3) 153 (36.6) 40 (9.4) 076 (17.9) 33 (7.8) 082 (19.4) An Anxiety and MI Complications 1003 4.428, p= 0.036 had main effects on the anxiety score tested by the multifactorial ANOVA. Patients in the single group, in which unmarried single, divorced, separated, and cohabitation were included, had higher anxiety than the married group or the widowed group (43.32± 13.20 vs. 38.51±12.73 and 37.36 ±11.47, respectively). Patients who received ASA in the emergency department had higher anxiety than those who did not (39.85 ±12.80 vs. 35.96±11.47). Patients who received anxiolytics in the emergency department had higher anxiety than who did not (42.82±12.01 vs. 37.59±12.90). Patients who received IV nitrate in the CCU had lower anxiety than those who did not (38.30±12.88 vs. 40.82 ±12.34). 3. Compare in-hospital complications between low vs. high anxiety groups Overall, 161 patients (38.0%) experienced at least one episode of in-hospital complication (i.e. ventricular tachycardia, ventricular fibrillation, reinfarction, recurrent ischemia or cardiac death). The percentage of patients who experienced any individual complication was less than 10% with the exceptions of sustained ventricular tachycardia (15.2%) and recurrent ischemia (23.3%). Ventricular fibrillation occurred in 21 subjects (5%), recurrent infarctions occurred in 9 subjects (2.1%) and cardiac death occurred in 5 subjects (1.2%) of the sample. Based on a median split, subjects’ SAI scores were divided into the following two groups: 1) above the median, and 2) below the median. The incidence of complications between the two groups was compared using Chisquare analyses. Comparison of the in-hospital compli- cations between the high and low anxiety groups measured by the SAI is shown in table 4. There were significant differences in the incidence of recurrent ischemia group compared to the low anxiety group experienced recurrent ischemia (27.5% vs. 18.9%). Overall, incidence of in-hospital complications was higher in the high anxiety group than in the low anxiety group (45.4% vs. 31.2%). 4. Effect of anxiety: testing significance of anxiety in predicting in-hospital complications. To identify potential risk factors including anxiety that predict in-hospital complications, univariate analyses were first performed. Sociodemographic and clinical characteristics that were significantly different between the complication and non-complication groups were identified using Chi-square tests for nominal and ordinal variables and independent t-tests for interval level variables (Table 5). Among sociodemographic variables, marital status was associated with the presence of overall complications. More subjects in the married group developed complications than in the single or widowed groups (74.5%, 16.1%, and 9.3%, respectively): x2 (2, N=424) = 6.437, p= 0.040. Patients who had diabetes experienced complications less often than those who did not have diabetes (16.3% vs. 83.8%); x2 (1, N=423) = 4.936, p=0.017. Among clinical characteristics, peak level of creatine kinase isoenzymes (CKMB) and left ventricular ejection fraction (LVEF) differentiated the complication and noncomplication groups. The mean value of peak CKMB was higher in the group with complications than in the non-complication group (173.93±193.00 ng/ml vs. Table 4. Complications by High and Low Anxiety Measured by the SAI Low Anxiety* n (%) High Anxiety* n (%) x2 p 27 (12.5) 7 (3.2) 37 (18.2) 6 (3.0) 2.657 3.556 0.068 0.169 9 (4.2) 1 (0.5) 12 (5.9)0 1 (0.5) 0.670 0.716 0.276 0.699 41 (18.9) 14 (6.5)0 3 (1.4) 1 (0.5) 68 (31.2) 56 (27.5) 23 (11.3) 6 (3.0) 4 (2.0) 93 (45.4) 4.350 4.834 1.241 2.143 9.029 0.024 0.089 0.222 0.167 0.002 VT any episode multiple episodes VF any episode multiple episodes Recurrent Ischemia any episode multiple episodes Re-infarction Cardiac death Any complication *groups formed using a split at the median of 37 of state anxiety 1004 Journal of Korean Academy of Nursing Vol. 32, No. 7 120.65±126.37 ng/ml): t (402)= -3.351, p= 0.001. The patients who had higher CKMB more often experienced complications than patients who had lower CKMB (56.6% vs. 43.4%). Left ventricular ejection fraction was lower in the complication group than in the non-complication group (49.26±12.25% vs. 52.39±12.01 %): t (290)=2.270, p=0.031. The patients who had lower LVEF more often experienced in-hospital complications than patient who had higher LVEF (81.0% vs. 19.0%). A logistic regression analysis was performed with the incidence of overall in-hospital complications as the outcome variable. Predictors identified from the univariate analyses were marital status, history of diabetes, CKMB and LVEF, and anxiety. In addition, age was included, despite its lack of association with complications on the univariate analysis in this sample, because of its potential clinical importance. Age was a predictor of in-hospital complications in a recent study (Moser & Dracup, 1996). Marital status, comorbidity with diabetes, level of CKMB, LVEF and age were first forced into the logistic regression model. Anxiety was then forced into the model. Table 6 shows the regression coefficients, Wald statistics, odds ratio and 95% confidential intervals for odds ratios for each of the seven predictors. A test of the reduced model with five predictors against a constant model was statistically significant indicating that the predictors, as a set, reliably distinguished between the complication group and the non-complication group: x2 (6, N=323)= 17.486, p=.0077. Prediction success was low for the complication group (13.28%) and high for the non-complication group with 92.31% correctly predicted. Successful prediction rate was acceptable at 60.99%. Introduction of anxiety to the regression model significantly improved the model in terms of the Goodness of Fit (321 vs. 324) and increment of Nagelkerke R2 (0.071 vs. 0.137): x 2 (2, N=323) = 16.99 , p=1003.002. According to the Ward criterion, anxiety measured by the SAI reliably predicted the occurrence of in-hospital Table 5. Sociodemographic and clinical factors that discriminate in-hospital complications Variables Marital status Married Single Widowed Diabetes Yes No CKMB* Below Above LVEF** Below Above Had any complications N (%) x2 df p 120 (74.5) 026 (16.1) 15 (9.3) 6.437 2 0.040 026 (16.3) 134 (83.8) 4.936 1 0.017 066 (43.4) 086 (56.6) 3.603 1 0.036 026 (19.0) 111 (81.0) 4.550 1 0.025 *CKMB = Creatine kinase isoenzyme MB: below = below median; above = above median **LVEF = left ventricular ejection fraction; below = below median; above = above median Table 6. Regression on In-Hospital Complications as Outcome and Seven Predictors Variable MARITAL STATUS DIABETES CKMB LVEF AGE SAI (CONSTANT) B Ward F Significance Odds ratio 0.2552 0.7055 -0.3317 1.0258 0.2501 0.5586 -0.2687 0.3869 5.4152 1.8775 8.5997 0.8761 4.0074 0.6574 0.5339 0.0200 0.1706 0.0034 0.3493 0.0435 0.4175 1.2907 2.0249 0.7177 2.7892 1.2841 1.7483 95% Confidence Interval for Odds Ratio Lower Upper 0.5776 1.1177 0.4465 1.4052 0.7607 1.0165 2.8847 3.6684 1.1535 5.5362 2.1678 3.0067 Legend CI= Confidence Interval (95%); SE= Standard Error *Model Chi-Square=33.465, df=6, p=.000 An Anxiety and MI Complications 1005 complications. Anxiety measured by the SAI (odds ratio = 1.75, 95% CI 1.01-3.01, p= 0.04) significantly contributed to the model. Patients who were in the high anxiety group were 1.8 times more likely to have in-hospital complications than those who were in the low anxiety group. This finding confirms that anxiety after AMI, after controlling other risk factors for the complications, is a reliable predictor of in-hospital complications. DISCUSSION Although any precise statistics are not available, significant number of death from AMI is consisted of in-hospital mortality. In-hospital mortality may be associated with the development of in-hospital complications. Development of complications is largely responsible for the 10-15% mortality rate in the early stage of AMI (Shah et al., 1994; Swan, 1991). Left ventricular dysfunction (Hendel, 1990), atrial fibrillation (Henning, 1975; Kannel & Abbott, 1987), supraventricular tachycardia (Henning, 1975), left bundle branch block (Henning, 1975), atrioventricular block (Tofler et al., 1987), recurrent ischemia, and reinfarction are common complications associated with in-hospital death. Anxiety is an important phenomenon in AMI patients because it may cause negative physiologic effects during recovery (Krantz, Helmers, Nebel, Gottniener, & Rosanski, 1990; Larson, Schneiderman, & Pasin, 1986; Lown & Desilva, 1978; Lown et al., 1980). Anxiety may contribute to in-hospital complications after AMI by exaggerating SNS activation. An activated SNS stimulates the release of catecholamines. Excessive catecholamines can induce hyperreactivity of the cardiovascular system (Bigger et al, 1992; Lown, DeSilva, Reich & Murawski, 1980; Vincent, 1994). Specifically, SNS arousal may increase coronary artery basal vascular tone (Panza, Epstein, & Quyyumi, 1991), increase platelet aggregation (Priori, Zuanetti, & Schwartz, 1988), increase intraluminal shearing forces, myocardial oxygen consumption, and decrease the fibrillation threshold (Karmarck & Jennings, 1991). Subsequently, SNS activation may exacerbate ischemia, contribute to the development of ventricular arrhythmias, and result in infarction and cardiac death (Karmarck & Jennings, 1991). These cardiac events can occur in the early stage of AMI, and are defined as in-hospital complications in this study. These complications are subsequently associated with in-hospital and one year mortality (Dittrich, Gilpin, & Nicod, 1988; Greenland, Riecher-Reiss, Goldbourt, Behar, & the Israeli SPRINT Investigators, 1991; Kannel, Sorlie, & McNamara, 1979; Maynard et al., 1997; Tofler et al., 1987). Overall findings of the sociodemographic and clinical characteristics of the sample in this study demonstrate that this sample was similar to that of other published studies (Dittrich, Gilpin, Nicod, 1988; Greenland, 1991; Hamilton & Seidman, 1993; Hendel, 1990; Kannel & Abbott, 1987; Maynard, 1991; Moser & Dracup, 1996). Thus we can conclude that no obvious bias was introduced in our sampling. The overall mean score of anxiety measured by the SAI was 39±13, and ranged from 18 to 80 in this study. Age specific normative values for persons aged 50 to 69 were 34.51±10.34 for men and 32.20±8.67 for women (Spielberger, 1983). The mean score of state anxiety of general medical surgical patients has been reported as 42.38 ±13.79. Therefore the overall mean score of anxiety on the SAI scale in this sample was higher than the normative value of the same age group, yet lower than the mean score of the general medical surgical patients. Comparisons of anxiety scores to previous studies are summarized in Table 7. Studies in which state anxiety had been measured during the stay in the CCU were selected for these comparisons. State anxiety scores were abstracted from either descriptive studies or the baseline anxiety of the intervention studies. However direct comparisons among studies may not appropriate because level of anxiety was measured in different time across studies. The presence of gender differences in anxiety and in the association between anxiety and in-hospital complications have been controversial. In this study, the mean score of anxiety was higher in women than in men (42.03±12.86 vs. 37.74±12.51). This gender differences in anxiety may support the previous investigators assumption that anxiety, in addition to the physiologic factors, may play an important role in gender difference in recovery and prognosis after AMI. Women show higher in-hospital and one year mortality and poorer health outcomes after AMI (Adams, Jemieson, Rawles, Trent, & Jennings, 1995; AHA, 1998; Greenland, ReicherReiss, Goldbourt, & Behar, 1991; Kannel & Abbott, 1987; Lerner & Kennel, 1986; Murabito, 1993; Tofler, Stone, 1987;Weaver, White, Wilcox, 1996). The older age of women when they experience an AMI partially explains their higher mortality. Anatomical and physio- 1006 Journal of Korean Academy of Nursing Vol. 32, No. 7 Table 7. Comparison of Anxiety Scores on SAI in Current Studies Author (Year) When anxiety was measured Anxiety scores Glick (1986) Cristies (1988) Zimmerman (1988) White (1992) Web & Riggin (1994) Rose et al. (1994) Elliott (1994) Hillers et al.(1994) Crowe (1996) Frasure-Smith et al. (1997) Present study (1999) within 3 hours after transferred from CCU 4 days after admission in CCU 72 hours of admission 24-48 hours prior to discharge from the hospital 24 hours after transferred from CCU in CCU before discharge 1-3 days after admission in CCU 72 hours after admission 35.37** 42.5±1.4 35.7±9.2 47.78±5.37* M:36.4/W:35.8** 39.2±10.8 38.6** 47.8±9 M43±10/W 43±11 45.70±497.40 39.14±12.77 *Only patients with STAI>40 were included; **SD not reported M= men; W= women logic differences in the cardiovascular system between men and women may also explain gender differences in the prognosis after AMI (Adams et al., 1995; Wingate, 1997). Numerous risk factors contribute to the development of complications and to subsequent mortality. Among socio-demographic variables, marital status was a significant discriminator of in-hospital complications. In addition, history of diabetes was also a significant predictor of in-hospital complication. Among the clinical variables CKMB and LVEF were significantly differentiate prevalence of in-hospital complications. In addition to these socio-demographic and clinical variables, anxiety was shown to play an important role in developing in-hospital complications. The group with higher anxiety had more in-hospital complications than did the group with lower anxiety. In addition, anxiety after controlling socio-demographic and clinical factors, independently predict in-hospital complications. Findings of a significant contribution of anxiety to the prediction of in-hospital complications are of interest because they demonstrate a directional relationship. In this study, cardiac events that occurred only after anxiety was measured were included as dependent variables. By controlling the time of anxiety and in-hospital complications measurement, greater strength was given to the assertion of association between anxiety and complications as directional. This method was chosen to improve the lack of directional relationship in previous studies. It was unclear in previous studies whether anxiety influenced the health outcomes or whether the poor health outcomes caused anxiety. Although any causal relationship cannot be addressed in this study, a directional relationship was addressed by controlling the time of mea- suring dependent and independent variables. Additionally, the findings of the logistic regression provided the likelihood of each predictor of development of in-hospital complications. Patients with low LVEF are approximately three times as likely to have complications compared to patients with high LVEF. Patients with diabetes were less likely to have complications. Patients with high anxiety are twice as likely to have complications. The significant contribution of anxiety to the prediction of in-hospital complication supported the proposed theoretical framework. Findings regarding contribution of each predictor were consistent with findings from previous studies with an exception of the contradictory role of the presence of diabetes. In most studies, patients with diabetes experienced more complications. In this study, however, patients with diabetes were less likely to experience complications. The lower incidence of complications in patients with diabetes might be due to the aggressive treatment along with health care providers’ appreciation of the negative effects of diabetes on the prognosis following AMI. CONCLUSION Findings from this study suggest important clinical implications. The overall high level of anxiety provides a rationale for health care providers to assess and treat patients’ anxiety as soon as possible. Although the exact time for the peak level of anxiety is not known, anxiety consistently is highest during the earliest measurements. This implies that the true peak level of anxiety may have been missed in many studies. Findings of a significant gender difference in anxiety suggest that women in particular should be assessed for An Anxiety and MI Complications 1007 anxiety during the early stage of AMI. Some investigators pointed out the underuse of anxiolytics for AMI patients. This study also revealed underuse of anxiolytic for women in emergency department. Considering its potential effects on the prognosis of AMI, anxiety should be treated as well as other physical symptoms early after AMI. References Adams, J. N., Jamieson, M., Rawles, J. M., Trent, R. J., & Jennings, K. P. (1995). Women and myocardial infarction: ageism rather than sexism? 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