LITERATURE MONITOR:
A REVIEW OF RECENTLY PUBLISHED
CLINICAL ARTICLES

SMOKING LINKED TO RISK FOR PNEUMOCOCCAL DISEASE

Smoking has been linked to yet another adverse effect: invasive pneumococcal disease. In a recent study by Nuorti et al, cigarette smoking was associated with a fourfold increase in the risk for invasive pneumococcal disease and exposure to passive smoking was associated with a more than twofold increase.

The researchers interviewed 228 immunocompetent patients age 18 to 64 years with invasive pneumococcal disease (ie, isolation of Streptococcus pneumoniae from a normally sterile site) and 301 control subjects. Fifty-eight percent of the patients and 24% of the control subjects were current smokers.

Smoking was the strongest independent risk factor for pneumococcal disease, with 51% of the disease burden attributed to smoking and 17% attributed to passive smoking. Patients were 4.1 times more likely to be current smokers and 2.5 times more likely to be exposed to environmental tobacco smoke than were controls.

Nuorti et al also found a dose-response relationship between smoking and the risk for pneumococcal disease (Figure 1). In addition, the length of time since smoking cessation and the level of passive exposure among nonsmokers was positively correlated with the risk.

The findings raise the question of whether all smokers should be vaccinated against pneumococci, noted John V. L. Sheffield, MD, and Richard K. Root, MD, in an accompanying editorial. While studies have shown that vaccination does not benefit older high-risk patients, the investigators suggested that immunocompetent, nonelderly smokers may have a better response.

 

Figure 1 Dose-Response Relationship Between Cigarette Smoking and the Risk for Invasive Pneumococcal Disease

Data extracted from Nuorti et al. N Engl J Med. 2000.

Nuorti JP, Butler JC, Farley MM, et al. Cigarette smoking and invasive pneumococcal disease. Active Bacterial Core Surveillance Team. N Engl J Med. 2000;342:681-689.
Sheffield JVL, Root RK. Smoking and pneumococcal infection. N Engl J Med. 2000;342:732-734.

REDUCING COLDS AMONG CHILDREN IN DAY CARE

A simple infection control technique significantly reduced the transmission of upper respiratory tract infections among children age 2 years and younger who attended day care, according to findings from a recent study by Roberts et al.

Eleven day care centers in an Australian city were assigned to an infection control intervention; 12 others served as control centers. The parents of 558 children were asked to report symptoms of illness every two weeks for nine months; 299 of these children attended the intervention centers, and the other 259 were enrolled at the control centers.

At the intervention centers, the staff was educated about transmission of infection and taught a hand-washing technique: Wash for 10 seconds and rinse for 10 seconds after using the bathroom, before eating, after a diaper change, and after wiping a nose (unless a small plastic bag had been used to cover the hand like a glove while the nose was wiped). The staff was also asked to teach this technique to the children and to wash the hands of children too young to do so unassisted.

Overall, the two groups of children had a similar number of colds. However, the intervention had a significant effect on children age 2 years and younger--the number of colds was reduced by 11% to 17% in centers that had high compliance with the recommended practices.

The intervention may have had an effect only on the children age 2 years and younger because they are least able to blow their own noses and wash their own hands, the researchers hypothesized. It is also possible the intervention only worked in the younger children because they are less mobile and have less contact with playmates than do older children.

This reduction in colds did not translate into a significant reduction in days absent from day care, however. As Roberts et al explained, "this is consistent with practice in Australia, where children with upper respiratory infection are rarely kept away from care."

Roberts L, Smith W, Jorm L, et al. Effect of infection control measures on the frequency of upper respiratory infection in child care: a randomized, controlled trial. Pediatrics. 2000;105:738-742.

ALLERGY CLINICS BENEFIT INNER-CITY ASTHMA PATIENTS

Inner-city asthma patients required fewer hospitalizations and emergency department (ED) visits and showed significant improvement in disease severity when treated in an allergy clinic instead of by primary care or ED physicians.

Vilar et al reviewed the medical records of 100 asthma patients treated at an allergy clinic for two consecutive years. The researchers compared the frequency of hospitalizations, ED visits, and asthma severity during the year before the patients began attending the allergy clinic and in the first and second years of treatment at the clinic.

The intervention included clinic visits every one to eight weeks, peak flow meter training and home monitoring, instruction on use of metered-dose inhalers and spacers, and optimal anti-inflammatory and bronchodilator dosages. In addition, the patients were taught about environmental control measures and received immunotherapy when indicated.

The frequency of hospitalizations and ED visits significantly declined over time once the patients began attending the clinic; the greatest decrease occurred during the first year of clinic treatment. Disease severity also significantly declined over time; not surprisingly, the greatest reduction was found among compliant patients.

In the second phase of the study, 23 patients from the allergy clinic and 21 patients treated by primary care or ED physicians completed a quality-of-life survey. Overall, scores were higher among patients treated in the allergy clinic than among those who received standard care; the only significant differences were found among answers focusing on mental health and social functioning, Vilar et al reported.

Vilar MEB, Reddy BM, Silverman BA, et al. Superior clinical outcomes of inner city asthma patients treated in an allergy clinic. Ann Allergy Asthma Immunol. 2000;84:299-303.

BRONCHIAL REACTIVITY IN CROHN'S DISEASE

Bronchial hyperresponsiveness is common among children and adolescents with Crohn's disease, even in those without evidence of respiratory problems, according to findings from a recent study. The data suggest that bronchial hyperresponsiveness "is likely to be the expression of subclinical airway inflammation," reported Mansi et al.

The researchers measured forced expiratory volume in one second (FEV1) in 14 patients with Crohn's disease, 10 patients with mild bronchial asthma, and 10 healthy nonatopic subjects. Subjects with an FEV1 above 80% of the predicted value underwent a methacholine challenge.

Bronchial hyperresponsiveness was found in 10 of the 14 patients with Crohn's disease (71%). Seven of these hyperresponsive patients were nonatopic. Hyperresponsiveness was also found in all of the asthma patients but in none of the control subjects.

Interestingly, the hyperreactive patients with Crohn's disease showed no signs or symptoms of respiratory problems. This finding "supports the supposition of subclinical airway involvement," noted Mansi et al.

Bronchial responsiveness was reevaluated in five patients with Crohn's disease a median of 25 months after the first test. The results showed a significant decrease in bronchial hyperreactivity over time. This decrease was not related to disease status or treatment.

Mansi A, Cucchiara S, Greco L, et al. Bronchial hyperresponsiveness in children and adolescents with Crohn's disease. Am J Respir Crit Care Med. 2000;161:1051-1054.

LEUKOTRIENE ANTAGONISTS AND CHURG-STRAUSS SYNDROME

Do leukotriene antagonists cause--or contribute to the onset of--Churg-Strauss syndrome in asthma patients? New evidence suggests that the answer is "no"; rather, these drugs seem to unmask an underlying systemic eosinophilic disorder that initially may have been characterized as moderate to severe asthma.

Wechsler et al came to this conclusion after examining four cases of Churg-Strauss syndrome in asthma patients (one man and three women) who were taking montelukast. In each case, the patient had a history of multiple asthma exacerbations requiring frequent courses of oral systemic corticosteroids or high doses of inhaled corticosteroids. At the time Churg-Strauss syndrome became manifest in each patient, the corticosteroid dose was being tapered.

These authors had previously reported eight cases in which Churg-Strauss developed in asthma patients being treated with zafirlukast. However, they have also found two cases in which the syndrome arose in patients given inhaled corticosteroids and salmeterol, but not a leukotriene antagonist. In all of these cases, the common factor was a reduction in the corticosteroid dosage.

Wechsler et al concluded, therefore, that "the high-dose inhaled corticosteroids used in these patients, in conjunction with intermittent systemic corticosteroid treatment, had suppressed manifestations of systemic eosinophilia." The association with leukotriene antagonists appears to be coincidental, not causal, they suggested.

The authors conceded the possibility that an allergic response to montelukast or zafirlukast may have played a role in some cases, although they consider this unlikely, given that the two drugs have distinctly different molecular structures. Thus, the controversy concerning this issue will continue.

Wechsler ME, Finn D, Gunawardena D, et al. Churg-Strauss syndrome in patients receiving montelukast as treatment for asthma. Chest. 2000;117:708-713.

PREDICTING OUTCOME OF SINUS SURGERY IN ALLERGIC PATIENTS

An increased number of cells expressing interleukin 5 messenger RNA (IL-5 mRNA) in the ethmoid sinuses may be used to predict which allergic patients with chronic rhinosinusitis will not benefit from surgery, a recent study suggests.

Lavigne et al studied 15 allergic patients who underwent ethmoidectomy for chronic sinusitis. All of the patients had perennial rhinitis and extensive bilateral mucosal disease on computed tomography scans of the sinuses. Biopsy of the inferior turbinate and of the most inflamed areas of the maxillary and ethmoid sinuses was used to determine the number of lymphocytes, mast cells and eosinophils, and cells expressing IL-4 and IL-5 mRNA in these areas at the time of surgery. These results were compared with two-year outcomes. Symptoms were worse or unchanged after surgery in about half of the patients (53%). The only significant difference between responders and nonresponders was a higher number of cells expressing IL-5 mRNA at the time of surgery in the ethmoid sinuses of nonresponders.

Lavigne et al determined that a test using an arbitrary cutoff of 11 or more IL-5 mRNA-positive cells per high-power field in the ethmoid sinuses would have a sensitivity of 86% and a specificity of 88% in differentiating potential responders from nonresponders to surgery.

Lavigne F, Nguyen CT, Cameron L, et al. Prognosis and prediction of response to surgery in allergic patients with chronic sinusitis. J Allergy Clin Immunol. 2000;105:746-751.

INCENTIVE PSIROMETRY: NOT USEFUL AFTER THORACIC SURGERY

Routine use of incentive spirometry appears to be ineffective in preventing postoperative pulmonary complications after thoracic surgery, new findings suggest.

Gosselink et al randomized 67 patients undergoing elective thoracic surgery for lung or esophagus resection to physiotherapy alone or physiotherapy plus incentive spirometry. Both groups were instructed to perform the following each hour after surgery: two series of five to 10 slow maximal inspiratory maneuvers with breath-holding, followed by forced expirations and coughing. The only difference was that the spirometry group performed the maximal inspiratory maneuvers with a volume feedback incentive spirometer.

In both groups, pulmonary function declined significantly after surgery and improved significantly by day 21. This recovery was similar between the two groups. The rate of pulmonary complications was relatively low in this study and was similar between the two groups (about 12% in each). The groups also had similar mean values for hospital and intensive care unit stays, white blood cell count, chest radiograph score, body temperature, and number of bronchoscopies.

The findings are in accordance with previous studies involving patients who underwent abdominal or cardiac surgery. "Although we cannot rule out beneficial effects in a subgroup of high-risk patients, routine use of [incentive spirometry] after thoracic surgery seems to be ineffective," Gosselink et al concluded.

Gosselink R, Schrever K, Cops P, et al. Incentive spirometry does not enhance recovery after thoracic surgery. Crit Care Med. 2000;28:679-683.