BackgroundFor patients with rare diseases (RD), misdiagnosis (or erroneous diagnosis) is one of the key issues that hinder RD patients’ accessibility to timely treatment. Yet, little is known about the main factors that are associated with RD patients’ misdiagnosis. The objective of this study is to analyze data from a national survey among 2040 RD patients from China to explore the association between misdiagnosis and various factors, including patients’ demographics, socio-economic status, medical history, and their accessibility to RD information.ResultsThree binary logistic regression analyses were performed to assess the relationships between misdiagnosis and level of rarity of the RDs (mild, moderate, and severe), demographics, health insurance levels, and accessibility to disease-related information by using the total sample, and the adult and non-adult sub-samples. We found that accessibility to RD information is the most critical factor influencing the patients’ chances of being misdiagnosed (odds ratio [OR] = 4.459, p < 0.001). In other words, the greater the difficulty in accessing the information on RD management, the higher the possibility of experiencing misdiagnosis.Such influences of information accessibility on misdiagnosis were repeatedly discovered when examining the adult (OR = 3.732, p < 0.001) and the non-adult (OR = 5.174, p < 0.001) sub-samples. The association between perceived economic status and misdiagnosis was only significant in the total sample. The only other factor significantly associated with misdiagnosis was disease multimorbidity: participants who reported no multimorbidity are less likely to experience misdiagnosis (OR = 0.42, p < 0.001).ConclusionsOur study indicated that patients with RDs who have difficulty in accessing disease-related information are two to five times more likely to have experienced misdiagnosis. Even after adjusting for the patients’ age, gender, economic levels, and education levels, the impact of information accessibility was still significant. Our finding highlights the importance of access to information in reducing misdiagnosis among RD patients.