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Question Posted 12/05/13:

I'm trying to collect data from all patients with MCI at baseline/screening from all cohorts.

I used DXSUM_PDXCONV_ADNIALL (downloaded on 18 Nov 2013) but also "Advanced Search (beta)" (to acquire info about axial MRI scans from patients with MCI at screening/baseline). I found five patients (RIDs 78, 190, 995, 1154 and 1226) who are in DXSUM with an AD diagnosis at screening/baseline (DXCURREN=3, DXCONV=1) but they are in the individual list I downloaded via "advanced search (beta)" as MCI patients at screening/baseline.

In addition, RIDs 332 and 4803 in DXSUM have an AD diagnosis at screening/baseline and RID 2201 has DXCHANGE=7 (reversion MCI to NL) at screening/baseline but all are down as MCI at screening/baseline in the individual list I downloaded.

What is their correct diagnosis at screening/baseline, please?

Also, I found several patients (with MCI) in the “advanced search (beta)” list I downloaded (RIDs 322, 460, 521, 542, 662, 788, 948, 964, 1091, 1181, 1335, 2017, 2071, 2084, 2103, 2110, 2111, 2192, 2270, 2296, 2314, 2370, 2382, 2402) but I could not find them in DXSUM. What could be the reason for that, please?

Thank you in advance.

Kind regards,
Response posted 12/10/13 by Danielle:
A large portion of your question has to do with differences between the diagnosis at the screening visit and the diagnosis at the baseline visit. In all phases of ADNI, a subset of the initial information to be collected was done at the screening visit and once an individual was deemed eligible for the study, that person returned for the "baseline" visit. There is a diagnosis given at both the screening and the baseline visit. The Clinical Core recommends the use of the diagnosis at baseline, because the diagnosis is based on a more complete evaluation of the individual. Because the images were acquired at the screening visit, the diagnosis linked to them in the IDA is the diagnosis at screen, so that accounts for some of the discrepancies.

As for individuals for whom you are able to access initial images, but cannot find them in the DXSUM file, the majority are screen failures or individuals that withdrew from the study. You can look them up in the REGISTRY file. If the VISCODE is "f" and an ADNI-1 subject, that person failed screening. RGCONDCT is another variable that may be informative, since it says whether or not the visit was conducted.
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