Reacción a "Bladder cancer patients with colour vision deficiency have lower survival rates than those without this visual impairment"

Is the study based on sound data and methods?

"Yes. On the one hand, the data comes from the TriNetX database, which includes medical records from 275 million anonymous patients, backed by standardised procedures. On the other hand, the study presents a retrospective cohort design, with a large sample of 135 controls and 322 patients with colour vision deficiencies (135 diagnosed with bladder cancer and 187 diagnosed with colorectal cancer)."

How does it fit in with previous work? What new information does it provide?

"Previous studies had already pointed out that colour blindness can make it difficult to visually detect blood, a key symptom of some cancers. The main novelty of this work is that it links colour vision deficiencies with worse survival outcomes in bladder cancer, but not in colorectal cancer".

Are there any important limitations to consider?

"Yes. This type of study does not allow us to infer direct causality, only an association between two variables, in this case bladder cancer and colour vision deficiencies. In addition, colour vision deficiencies are often underdiagnosed, so there could be classification errors in the control group. These errors could have reduced the association with bladder cancer, but they could also have prevented the association with colorectal cancer from being detected."

How relevant is this study in practice/clinical settings? What recommendations can we make based on it?

"The study suggests that colour blindness could be an indirect risk factor for late diagnosis of bladder cancer, as one of the first signs of this disease is the presence of blood in the urine, which people with colour vision deficiencies may not easily detect. In practice, it reinforces the importance of not relying solely on patient observation and of considering more proactive screening or follow-up strategies, something that is highlighted by the results of this study in relation to people with colour blindness, but which would also benefit patients with normal vision. Finally, it emphasises the need to raise awareness among healthcare professionals and patients about this possible diagnostic bias."