Project ID: Visits and Conversion Reports for ADRC
Investigator: Daniel L Gillen, Ph.D, Director DMSC
Statistician: Michael J Phelan
DATA SOURCE: Dan Hoang, UCI MIND ADRC Data Management and Statistics Core

Background

The ADRC longitudinal cohort has followed patients since 1988. The Uniform Data Set (UDS) was implemented in 2005, standardizing much of the clinic’s data collection across all ADRC’s in the nation. After an initial baseline visit, patients are assessed annually for memory impairment. This report describes the frequency of patient visits for the cohort. Note that patients with greater than 7 visits were seen at the clinic prior to the implementation of the UDS in 2005, when some of the data collection procedures changed.

This report is divided into two parts covering visit and conversion frequencies for all ADRC participants. All analyses were carried out in the programming and computing environment R (R Core Team 2018).

Visit Report

The visits report provides tables and graphs of the frequencies of visits among ADRC participants. Visit frequencies are shown based on initial status and recent status. The following tables and figures are included in the visit report.

Tables and Figures

  1. Table 1 of Visit Frequencies by Initial Status.
  2. Table 2 of Visit Frequencies by Recent Status.
  3. Figure 1 of Visit Frequencies by Initial Status.
  4. Figure 2 of Visit Frequencies by Recent Status.

Frequency of visits by initial status

Table 1: Frequency of Visits by Initial Status. Rows designate the initial status. Columns the frequency of visits from 1 to 10 or more. Row frequencies described the number of participants by status.
Initial Status
Frequency of Visits
1 2 3 4 5 6 7 8 9 \(\geq 10\) Total
Normal 216 22 3 1 8 18 13 10 8 0 299
QCI 54 7 1 1 1 1 3 3 0 2 73
MCI 191 12 3 2 2 3 5 6 7 2 233
Dementia 77 16 9 8 10 6 6 7 4 2 145
Total 538 57 16 12 21 28 27 26 19 6 750
Note:
Summaries include both active and deceased patients.

Frequency of visits by recent status

Table 2: Frequency of Visits by Recent Status. Rows designate the recent status. Columns the frequency of visits from 1 to 10 or more. Row frequencies described the number of participants by status.
Recent Status
Frequency of Visits
1 2 3 4 5 6 7 8 9 \(\geq 10\) Total
Normal 27 35 37 34 14 10 12 13 14 61 257
QCI 14 7 7 9 7 4 5 5 4 15 77
MCI 23 19 18 10 9 10 8 9 6 24 136
Dementia 8 31 32 26 23 30 33 22 14 61 280
Total 72 92 94 79 53 54 58 49 38 161 750
Note:
Summaries include both active and deceased participants.

Frequencies of visits by initial status

Frequency of Visits by Initial Status. Status refers to Normal, MCI, QCI and Dementia. Each chart designates an initial status and bars are labeled by frequency of visit from 1 to 10 or more.

Figure 1: Frequency of Visits by Initial Status. Status refers to Normal, MCI, QCI and Dementia. Each chart designates an initial status and bars are labeled by frequency of visit from 1 to 10 or more.

Frequencies of visits by recent status

Frequency of Visits by Recent Status. Status refers to Normal, MCI, QCI and Dementia. Each chart designates a recent status and bars are labeled by frequency of visit from 1 to 10 or more.

Figure 2: Frequency of Visits by Recent Status. Status refers to Normal, MCI, QCI and Dementia. Each chart designates a recent status and bars are labeled by frequency of visit from 1 to 10 or more.

Conversion Report

The conversion report provides tables and graphs of the conversion frequencies among ADRC participants. Conversions are shown for participants based on their Normal, MCI, QCI, or Dementia status. The following tables and figures are included in the conversion report.

Tables and Figures

  1. Table 3 of Conversion Frequencies.
  2. Table 4 of Conversion Rates.
  3. Figure 3 of Conversion Frequencies by Conversion Status.

Conversion from Initial to Latest Status

Table 3: Number of Conversions from Initial Status to Latest Status. Rows designate the initial status. Columns the latest status. Row frequencies described the number of conversions from intitial to latest status. Rows sum to 100%.
Initial status
Latest status
Normal QCI MCI Dementia Total
Normal 235 (78.6%) 27 (9%) 28 (9.4%) 9 (3%) 299 (100%)
QCI 11 (15.1%) 39 (53.4%) 14 (19.2%) 9 (12.3%) 73 (100%)
MCI 11 (4.7%) 11 (4.7%) 94 (40.3%) 117 (50.2%) 233 (100%)
Dementia 0 (0%) 0 (0%) 0 (0%) 145 (100%) 145 (100%)
Total 257 77 136 280 750
Note:
Note that summaries include both active and deceased patients.

Conversion Rate per 100 Person-Years

Table 4: Conversion Rate per Person-Years Based on Conversion Status. Rows designate the conversion status. Summary statistics describe the number of cases, person-years of follow up, estimated conversion rate per 100 person-years, and a 95% confidence interval for the population value.
Conversion status
Summary
Cases Person-years Rate 95% CI
Normal\(\rightarrow\) QCI 27 1499.82 1.8 (1.23, 2.63)
Normal\(\rightarrow\) MCI 28 1632.55 1.715 (1.18, 2.48)
Normal\(\rightarrow\) Dementia 9 1702.19 0.529 (0.28, 1.02)
QCI\(\rightarrow\) Normal 11 135.98 8.089 (4.48, 14.61)
QCI\(\rightarrow\) MCI 14 181.07 7.732 (4.58, 13.06)
QCI\(\rightarrow\) Dementia 9 256.35 3.511 (1.83, 6.75)
MCI\(\rightarrow\) Normal 11 617.46 1.781 (0.99, 3.22)
MCI\(\rightarrow\) QCI 11 868.8 1.266 (0.7, 2.29)
MCI\(\rightarrow\) Dementia 117 669.31 17.481 (14.58, 20.95)
Dementia\(\rightarrow\) Normal 0 464.72 0 (0, NaN)
Dementia\(\rightarrow\) QCI 0 464.72 0 (0, NaN)
Dementia\(\rightarrow\) MCI 0 464.72 0 (0, NaN)
Note:
Participants were considered at risk for converting back to normal from the date of first diagnosis of QCI to the minimum of first diagnosis of MCI, dementia, death, lost to follow-up, or end of study for any reasons. A parallel rule was applied for backward conversion from, say, MCI to Normal status.

Conversion Frequencies by Conversion Status

Conversions based on Initial Status and Latest Status. Status refers to Normal, MCI, QCI and Dementia. Each chart designates an initial status and bars are labeled by the latest status. Frequencies described the number of conversions from intitial to latest status.

Figure 3: Conversions based on Initial Status and Latest Status. Status refers to Normal, MCI, QCI and Dementia. Each chart designates an initial status and bars are labeled by the latest status. Frequencies described the number of conversions from intitial to latest status.

Citations

R Core Team. 2018. R: A Language and Environment for Statistical Computing. Vienna, Austria: R Foundation for Statistical Computing. https://www.R-project.org/.