The HHT survey benefited from targeting a group with high proportions requiring long term iron therapy, and highly motivated to participate in research studies as evidenced by the rapid response rate. The survey of self-reported tolerance or iron tablets and anemia is the weakest component of the current study, particularly as it did not include a placebo group for medications where Kerr and Davidson elegantly demonstrated suggestibility of side effects. [65] The data are included because they provide a further large series that suggests high proportions of patients have to limit or modify their iron treatments, and that poor toleration of iron tablets is associated with persistent anemia. Since actual blood loss from nosebleeds may be greater than stated due to hemorrhaged blood that is swallowed, the nosebleed-based estimation may be an underestimation for some patients. A minor weakness of the study was that the rate of each individual bleeding event was not available, and instead calculated from patient reports of timed nosebleed volumes, applied according to reported intensity which effectively distinguishes arterial and non arterial bleeding.