Description:
Home spirometry devices allow for the monitoring of pulmonary function in the home. Their primary proposed use is by lung transplant recipients to aid in the early diagnosis of infection and rejection. They can potentially also be used in other situations that require pulmonary function monitoring.

In the immediate postoperative period, lung transplant recipients must be carefully monitored for the development of either rejection episodes or infectious complications. Monitoring techniques include complete pulmonary function testing, serial chest X-rays, bronchioalveolar lavage and transbronchial biopsy. Transbronchial biopsy is thought to be the only objective method of distinguishing between these two common complications. Transbronchial biopsy is typically performed on a routine schedule, with additional biopsies performed if the patient becomes symptomatic. Home spirometry is proposed as a technique to provide daily monitoring to promptly identify presymptomatic patients who may benefit from a diagnostic transbronchial biopsy.

Home spirometry uses battery operated spirometers that permit regular daily measurement of pulmonary function in the home, typically forced expiratory volume in one second (FEV-1) and forced vital capacity (FVC). The device has been primarily investigated among lung transplant recipients as a technique to provide early diagnosis of infection and rejection. Home spirometry may also be referred to as ambulatory spirometry.

Policy:
Home monitoring of pulmonary function is considered INVESTIGATIONAL.

Policy Guidelines
In 1999, a series of 3 new CPT codes were introduced that specifically describe patient-initiated spirometric recording (i.e., home spirometry) as follows:

94014: Patient-initiated spirometric recording per 30-day period of time; includes reinforced education, transmission of spirometric tracing, data capture, analysis of transmitted data, periodic recalibration and physician's review and interpretation

94015: Recording (includes hook-up, reinforced education, data transmission, data capture, trend analysis and periodic recalibration)

94016: Physician review and interpretation only

Benefit Application
BlueCard/National Account Issues
Global case rates for lung transplantation that provide for a period of outpatient care may include the use of home spirometry.

Rationale:
In 1999, when the policy was created, published data were minimal. Otulana and colleagues reported on the use of home spirometry in an initial case series of 15 heart-lung transplant recipients.¹ The authors hypothesized that the results of routine spirometry might better guide the use of transbronchial biopsy. They reported that episodes of rejection or infection were associated with a 10 percent decrease in FEV-1 and recommended that this decrease should prompt a transbronchial biopsy. However, all patients also had symptoms at the same time, so it is unclear how the spirometry contributed to the decision to perform a transbronchial biopsy. On nine occasions, the FEV-1 was unchanged at the time of a routine scheduled transbronchial biopsy. Histologic results were normal in these patients.

Fracchia and colleagues reported on a case series of nine heart-lung transplant recipients who underwent monitoring of lung rejection with home spirometry.² Similar to the study of Otulana, patients underwent a "symptom" transbronchial biopsy if their FEV-1 or FVC showed a decrease of 10 percent. Only three patients underwent a symptom biopsy, which revealed moderate rejection. It was not reported whether the patient was clinically symptomatic at that time. In addition, during routinely scheduled transbronchial biopsies, acute rejections were observed even in the face of normal FEV-1 values.

In summary, when the policy was created, the paucity of published clinical data did not permit scientific conclusions regarding the clinical use of home monitoring of FEV-1 and FVC. Specifically, there were inadequate data to determine how reductions in FEV-1 and FVC relate to clinical symptoms, and how this information can be used to determine the necessity of transbronchial biopsies.

Updates:
A retrospective cost analysis published in 2007 evaluated home monitoring in 138 lung transplant recipients who were monitored for at least one year.³ The analysis found that adherence to a program of home monitoring that included home spirometry was associated with lower overall costs (higher outpatient, lower inpatient). However, there was no comparison group of patients with lung transplant who did not have home monitoring and there are likely patient factors that impact adherence and preclude attributing the cost savings to the program.

A 2009 study conducted in Germany reported on results of a prospective study comparing outcomes seven years post-transplant in lung transplant recipients who did and did not adhere to a 2-year program of home spirometry, beginning six months after the transplant.⁴ A total of 271 patients met eligibility criteria and were invited to participate; of these, complete home spirometry data over two years was available for 226 (83 percent) participants. Follow-up data at seven years was available for 183 of the 226 patients (81 percent) who completed home spirometry measurements; excluded were 36 patients who died and seven who were lost to follow-up. Patients were placed in the following three categories according to their use of home spirometry: good adherers (performed at least 80 percent of expected home spirometry), moderate adherers (performed between 50 percent and 79 percent of expected home spirometry) or non-adherers (performed less than 50 percent of expected home spirometry). Adherence was rated separately for each of four six-month periods (months 6 – 12, months 13 – 18, months 19 – 24 and months 25 – 30). Adherence was highest during the first six-month period; over 80 percent of participants were considered good adherers. The proportion of good adherers decreased to about 70 percent in the second period, and then to about 55 percent during both the third and fourth periods. Over the seven years of follow-up, bronchiolitis obliterans syndrome developed in 72 out of 226 (31.9 percent) patients. According to Kaplan-Meier event-free analysis, there was a significantly lower freedom from bronchiolitis obliterans syndrome time in non-adherers compared with good or moderate adherers (p < 0.014). However, the re-transplantation rate and mortality rate were not significantly associated with home spirometry adherence; 5 percent of patients received a second transplant and the mortality rate was 20 percent. While this study reported the association between spirometry and health outcomes, it was not randomized, and although the authors attempted to control for risk factors, there may be differences between groups that affected adherence and impacted disease status.

Several studies have addressed home spirometry for patients other than lung transplant recipients. A 2007 publication reported results on using home spirometry to detect pulmonary complications in recipients of allogeneic stem cell transplants.⁵ While the authors concluded it was a useful procedure, further investigation is needed to determine potential impact on outcomes. Another study included 50 asthmatic children aged 6 to 17 years.⁶ This was a sequence randomized study measuring peak expiratory flow and FEV-1 using both a hospital-based pneumotachograph and a home spirometer (Koko Peak Pro). The study found both clinically and statistically significant differences between measures obtained using the two techniques in a controlled (professionally supervised) clinical setting. The results from each meter were reproducible but not interchangeable. The mean values for both measures were significantly lower when using the home spirometer compared to the hospital spirometer. This study also had the limitation that it did not report on the impact of home spirometry on outcomes.

Summary:
There are few studies on home spirometry use and most of the available literature did not evaluate the impact of home spirometry use on health outcomes. Only one study, which was from Germany and not randomized, evaluated health outcomes. Its findings were that adherence to home spirometry was associated with bronchiolitis obliterans syndrome but not mortality or re-transplantation. The evidence is insufficient that home spirometry improves the net health outcome and, thus, the technology is considered investigational.

References:

1. Otulana BA, Higenbottam T, Ferrari L et al. The use of home spirometry in detecting acute lung rejection and infection following heart-lung transplantation. Chest 1990; 97(2):353-7.
2. Fracchia C, Callegari G, Volpato G et al. Monitoring of lung rejection with home spirometry. Transplant Proc 1995; 27(3):2000-1.
3. Adam TJ, Finkelstein SM, Parente ST et al. Cost analysis of home monitoring in lung transplant recipients. Int J Technol Assess Health Care 2007; 23(2):216-22.
4. Kugler C, Fuehner T, Dierich M et al. Effect of adherence to home spirometry on bronchiolitis obliterans and graft survival after lung transplantation. Transplantation 2009; 88(1):129-34.
5. Guihot A, Becquemin MH, Couderc LJ et al. Telemetric monitoring of pulmonary function after allogeneic hematopoietic stem cell transplantation. Transplantation 2007; 83(5):554-60.
6. Brouwer AF, Roorda RJ, Brand PL. Comparison between peak expiratory flow and FEV(1) measurements on a home spirometer and on a pneumotachograph in children with asthma. Pediatr Pulmonol 2007; 42(9):813-8.

Coding Section

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.

This medical policy was developed through consideration of peer-reviewed medical literature generally recognized by the relevant medical community, U.S. FDA approval status, nationally accepted standards of medical practice and accepted standards of medical practice in this community, Blue Cross Blue Shield Association technology assessment program (TEC) and other nonaffiliated technology evaluation centers, reference to federal regulations, other plan medical policies and accredited national guidelines.

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