Outpatient parenteral antibiotic therapy. Management of serious infections. Part II: Amenable infections and models for delivery. Osteomyelitis

Outcomes of osteomyelitis among patients treated with outpatient parenteral antimicrobial therapy

PURPOSE

To examine the effects of diabetes, vascular disease, age, and antimicrobial therapy on clinical outcomes, including amputation rates, in patients with osteomyelitis treated in the outpatient setting.

METHODS

We performed a retrospective chart review of patients treated with intravenous antimicrobial therapy for osteomyelitis at an outpatient infectious diseases practice. All patients were followed for at least 6 months.

RESULTS

Four hundred and fifty-four patients qualified for inclusion, with follow-up information available for up to 10 years. One hundred and thirty-nine patients (31%) had recurrences and 27 (6%) had amputations. Of the recurrences, 108 (78%) occurred within 6 months and 132 (95%) within 1 year. In univariate analyses, peripheral vascular disease, diabetes, and the combination were all associated with the risk of recurrence; age (>70 years) was not. For osteomyelitis due to Staphylococcus aureus, the relative risk of recurrence, using a Cox regression model, was 0.8 for ceftriaxone (95% confidence interval [CI]: 0.4 to 1.5; P = 0.53), 1.1 for cefazolin (95% CI: 0.5 to 2.2; P = 0.80), and 2.5 for vancomycin (95% CI: 1.1 to 5.6; P = 0.04), as compared with the use of a penicillinase-resistant penicillin.

CONCLUSION

Diabetes and peripheral vascular disease are important factors in determining the prognosis of patients with osteomyelitis, but age is not. Almost all recurrences of osteomyelitis occur within 1 year. Recurrence rates with osteomyelitis associated with S. aureus appear to be higher with the use of vancomycin, whereas ceftriaxone and cefazolin appear to be similar to penicillinase-resistant penicillins.

Once-daily ceftriaxone out-patient therapy for superficial wound infection following major orthopaedic operation

We undertook a prospective open, non-randomised study to determine the efficacy of out-patient treatment of postoperative superficial wound infection, in patients with orthopaedic implants using single daily IM injection of ceftriaxone and to examine the cost effectiveness when compared with inpatient management. The study comprised of 25 patients who have had primary total hip or knee replacements or Dynamic Hip Screw fixation for an intertrochantric fracture. The superficial wound infections were categorised into mild, moderate and severe according to the classification described in this article and the length of administration of antibiotic varied according to the severity of infection. There were no failures in the study. It was estimated that an overall cost savings of £33.840 could be achieved. We recommend that superficial wound infection in association with major orthopaedic operations using implants can be managed with ceftriaxone as an out-patient.

Experience with a physician-directed, clinic-based program for outpatient parenteral antibiotic therapy in the USA

The experience with 538 patients who received outpatient parenteral antibiotic therapy (OPAT) in 1993 in a private institute in Tacoma, Washington, USA, is reviewed here. Clinical outcomes suggested a successful resolution of infection in 99% of cases. Bacteriological outcomes showed that eradication of the organism had occurred in 92% of patients by the end of therapy. The success of the program indicates that 91% of properly selected patients can be treated without adverse events. Antibiotics were changed in 45 (8%) instances, but only half of these changes were made because of an adverse event. The development of rash was the most frequent adverse event and resulted in hospitalization in only 1 instance. Hospitalization was necessary before the OPAT program was completed in 42 cases--20 of those were for surgery and 13 for medical reasons unrelated to the infection or antibiotic therapy. In 8 cases, patients were hospitalized because of failure of home care or inability to administer the antibiotics effectively. Three patients were taken off the program because of failure to comply. Patient satisfaction surveys suggested that 99% of patients were satisfied with the program. With careful patient selection and a well-developed program, OPAT can be safe, effective and beneficial to patients and can save costs in healthcare services.