Background

People with connective tissue disease such as rheumatoid arthritis and systemic sclerosis may develop a group of lung diseases called interstitial lung disease. This can affect breathing and quality of life, and can lead to a reduced life span. A drug called cyclophosphamide has been useful in treating other illnesses, but it has side effects.

Review question

We wanted to know if cyclophosphamide helped preserve lung function in people with interstitial lung disease due to connective tissue disease. We also wanted to look at whether the drug causes side effects, and if it helps improve peoples’ quality of life, length of life, breathing, and ability to exercise.

Study characteristics

We searched for studies up to May 2017, and we included four studies involving a total of 495 people with interstitial lung disease due to connective tissue disease. Some people were given cyclophosphamide, and others were given other drugs or a placebo. We compared these different groups to look for differences.

Key findings

We found some low-quality evidence showing small benefit of using cyclophosphamide compared with placebo in terms of lung function and symptoms of breathlessness. No clear evidence shows that people who took cyclophosphamide had better lung function than people who took a different drug (mycophenolate mofetil). Some people experienced low blood counts, blood in their urine, and nausea.

Quality of the evidence

We rated the quality of the evidence using one of the following grades: very low, low, moderate, or high. A rating of very low-quality evidence means that we are uncertain about the results. A rating of high-quality evidence means that we are very certain about the results. For this Cochrane review, we found evidence of low quality. We included randomised controlled trials that were blinded, which means that participants and those people who assessed study results did not know whether participants had received cyclophosphamide or a placebo. However, the trials mostly included people with systemic sclerosis, so these results may not apply to all people with interstitial lung disease with connective tissue disease.